Intracardiac echocardiography during simulated aortic and mitral balloon valvuloplasty: In vivo experimental studies The feasibility of intracardiac echocardiography with a low-frequency transducer to assess catheter position and detect complications during experimental aortic and mitral balloon vaivuiopiasty was studied in 10 dogs. Intracardiac echocardiography was performed with a transesophageai echocardiographic probe placed in the right atrium. in ail instances high-quality images of cardiac structures were obtained. The guide wire and balloon catheter were clearly seen as they crossed the valves. With Inflation the balloon was seen as a hyperechoic structure. Doppler echocardiography documented aortic regurgitation after inflations. Acute pericardiai effusion was instantly detected. it is concluded that intracardiac echocardiography is a potentially useful technique for cardiac imaging, assessing wire and balloon catheter position, evaluating vaivuiar regurgitation, and instantly detecting acute pericardiai effusion. Further research in humans with low-frequency, catheter-based transducers needs to be performed. (AM HEART J 1992; 123:665.)

Steven L. Schwartz, MD, Natesa G. Pandian, MD, Rohit Kumar, MD, Sarah E. Katz, BA, Brenda S. Kusay, BS, Mark Aronovitz, BA, Marvin A. Konstam, MD, and Deeb N. Salem MD. Boston, Mass.

Fluoroscopic imaging has been the standard technique used to guide interventional cardiac procedures. This modality often relies on crude fluoroscopic landmarks to determine catheter location. Blood vessel walls, cardiac walls, and valves cannot be directly imaged unless they are calcified. Contrast angiography allows for the visualization of the vessel lumen and cardiac chamber. However, one can only see a two-dimensional view of the structure opacified. The morphology of the vessel wall or cardiac chamber in question is determined by inference, based on the characteristics of the lumen. Additionally, radiation and contrast dyes have potential adverse affects that must be considered before these techniques are performed. These limitations of conventional imaging have been the impetus for the development of imaging modalities that could provide more detailed information and aid in decreasing the use of fluoroscopic radiation and contrast angiography. One of these, intravascular ultrasound imaging, is an ex-

From the Departments of Medicine Center Hospitals, Tufts University Received

for publication

Reprint requests: 750 Washington 4/l/34349

April

and Radiology, New School of Medicine.

1, 1991;

Steven L. Schwartz, St., Box 70, Boston,

accepted MD, New MA 02111.

England

Medical

Aug. 20, 1991. England

Medical

Center,

citing technique that is being evaluated for the study of various features of atherosclerotic vessels, including severity of stenosis, composition of the lesion, and response to interventional therapy.le6 This method uses catheter-based, high-frequency (20 to 40 MHz) transducers and yields detailed, high-resolution images. However, the depth of field is limited at these ranges of ultrasound frequency. With lower frequency transducers, ranging from 5 to 12.5 MHz, imaging at a larger depth of field is possible. Experimental studies by us and others, which explored the intracardiac imaging potential of low-frequency transducers, suggested that the entire heart could be imaged with such a transducer probe from one intracardiac location.7*8 By imaging with a 5 MHz transducer in the right atrium, information such as ventricular function and valve morphology and function were readily obtainable.7l g This technique could be potentially useful for monitoring cardiac function during interventional procedures. A recent report demonstrates the potential utility of intracardiac echocardiography during transcatheter closure of atria1 septal defects in experimental preparations.lO Another area where intracardiac ultrasound imaging might be of benefit is during percutaneous balloon valvuloplasty. The information gained from echocardiographic guidance could assist with posi665

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Fig. 1. Schematic diagram of views obtainable with transducer tip in different locations in right atrium. 1, Transducer tip high in right atrium (RA). 2, Probe in midportion of RA. 3, Imaging from inferior portion of RA. 4, Imaging from inferior vena cava. Ao, Aorta; AP, left atria1 appendage;L, left coronary cusp of aortic valve; LA, left atrium; LV, left ventricle; LVOT, left ventricular outflow tract; N, noncoronary cusp of aortic valve; PA, pulmonary artery; PV, pulmonic valve; R, right coronary cusp of aortic valve; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; SVC, superior vena cava.

tioning the guide wire and balloon catheters optimally to ensure the best results. Valvular morphology and function could be determined immediately before and after the procedure. Complications that typically arise from inappropriate placement of the wire or catheter could potentially be prevented or easily detected. Cardiac perforation, perhaps the most dreaded of these complications, is not uncommon. In a recently published report of balloon mitral valvuloplasty, among 75 procedures there were nine cardiac perforations; seven of these patients had car-

diac tamponade, four required emergency surgery, and two died.i’ Severe hemodynamic embarrassment after myocardial perforation can be prevented only by prompt recognition and treatment. The time delay introduced by waiting for an echocardiographic study may not be optimal for patient care during an emergency such as acute hemopericardium. The presence of an imaging catheter within the vascular system would aid in the detection of these complications and therefore facilitate treatment. This experimental study was undertaken to examine the con-

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2. Intracardiac echocardiographyduring experimental aortic valvuloplasty; short-axis view through aortic root. Partially inflated balloon catheter (B) is seenasbright echodensity in center of aorta (Ao). PA, Pulmonary artery.

Fig.

cept that intracardiac echocardiography could be useful during aortic and mitral balloon valvuloplasty by aiding in the placement of the balloon catheter and in the detection of complications such as valvular insufficiency and acute pericardial effusion. We addressed this in normal dogs during the performance of balloon valvuloplasty of the aortic and mitral valves. METHODS

Ten mongreldogs(weight 20to 35 kg) were anesthetized with sodiumpentobarbital. After endotrachealintubation, the lungs were ventilated with room air. An 8F introducer sheathwasplacedin the right jugular vein and a 12F sheath in the right femoral artery. A laparotomy was performed and the inferior vena cava isolated below the renal veins. A modified transesophagealechocardiographicprobe with a 5 Hz transducer (Hewlett-Packard Medical Products, Andover, Mass.) wasintroduced through a venotomy in the inferior vena cava and passedinto the right atrium. This probe was interfaced with a Hewlett-Packard echocardio-

graphic instrument, and baselinetwo-dimensional, color flow, and pulsed Doppler imageswere recorded on videotape. Different imaging planes were brought into view by advancing or withdrawing the probe, rotating the probe, or manipulating the controls on the handle. Aortic balloon valvuloplasty. Aortic valvuloplasty was performed in 8 dogswith an 11.5F, 18 mm balloon catheter (Boston Scientific Corp., Mansfield Div., Mansfield, Mass.). The balloon catheter wasintroduced into the aorta via the femoral arterial sheath, and under fluoroscopic guidance the aortic valve wascrossedwith the use of a guide wire. The balloon catheter waspositionedacrossthe aortic valve. Intracardiac echocardiographic imaging from the right atrium was instituted to evaluate whether the balloon catheter and its positioning acrossthe aortic valve could be visualized. The position of the catheter was confirmed by fluoroscopy and hemodynamic pressure wave form. The balloonwasinflated with an agitated mixture of salineand Renografin.A total of 16balloon inflations wereperformed. Echocardiographic imageswere recorded before, during, and after balloon inflation. Color Doppler imagingwasalso performed to assessthe presenceof aortic insufficiency.

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Fig. 3. Long-axis view of left ventricular outflow tract during experimental aortic valvuloplasty. Balloon catheter (BAL) is fully inflated, occupying entire diameter of outflow tract. Proximal end of balloon is in aorta (Ao) and distal end in left ventricle (Lv). Borders of catheter are clearly delineated. PA, Pulmonary artery.

The area of the color jet was used to determine the severity of regurgitation, with a larger jet area signifying increasing severity. Mitral balloon valvuloplasty. In four dogs a left lateral thoracotomy was performed. An llF, 12 mm valvuloplasty catheter (Boston Scientific Corp., Mansfield Div., Mansfield, Mass.) was passed into the left atria1 appendage through a stab wound and held in place with a pursestring suture. A guide wire was introduced into the left atrium through the balloon catheter. By means of fluoroscopic imaging and intracardiac echocardiography for guidance, the guide wire was then advanced across the mitral valve into the left ventricle. The balloon catheter was passed over the wire and across the mitral valve. Intracardiac echocardiographic images were obtained to confirm the position of the balloon catheter. The balloon was inflated with an agitated mixture of saline and Renografin. Balloon inflations were visualized with intracardiac echo imaging. A total of eight inflations were performed. Acute pericardial effusion. To simulate the condition of

acute hemopericardium that could result from cardiac perforation, intracardiac echocardiography was carried out during the production of an acute experimental pericardial effusion in six dogs. In four dogs access to the pericardium was obtained via a small subxiphoid incision; a 7F pigtail catheter was introduced into the pericardium, the pericardial opening was tightly sealed by a pursestring suture, and the access route was closed. In two dogs a midline sternotomy was performed, and the pigtail catheter was placed in the pericardial space through a pericardial incision and held in place by a pursestring suture. The chest was closed. Fluid-filled catheters were positioned in the right atrium and left ventricle through the previously placed venous and arterial sheaths and connected to pressure transducers. The intrapericardial catheter was used for both pressure measurement and fluid infusion into the pericardial cavity. Acute pericardial effusion was produced by rapidly infusing graded amounts of normal saline solution into the pericardial space until cardiac tamponade was produced. Cardiac tamponade was defined as equilibration of right atrial,

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views of aortic insufficiency jet after balloon inFig. 4. Short-axis (left) and oblique long-axis (right) flation asdisplayed by color flow mapping with intracardiac echocardiography.AI, Aortic insufficiency jet; RA, right atrium; RV, right ventricle.

pericardial, and diastolic left ventricular pressures.Intracardiac echocardiographic images were recorded in the control state, intermittently during salineinfusion, and at tamponade. Echocardiographic imageswere reviewed to assess the presenceof echocardiographicsignsof tamponade-right ventricular diastolic collapse and right atria1 collapse. After completion of the protocol, the dogswere killed by sodiumpentobarbital overdose.These studies conform to the “Position of the American Heart Association on Research Animal Use” and were approved by the New England Medical Center Animal ResearchCommittee. RESULTS

In all dogs the various cardiac chambers and valvular structures were visualized in multiple views, illustrated schematically in Fig. 1. With imaging from high in the right atrium, the superior vena cava, ascending aorta, and pulmonary artery were brought into view. With the transducer in the midportion of the right atrium, the ascending aorta and aortic valve in the short-axis view, the right ventricular outflow tract, pulmonary artery, and left atrium could be seen. Images analogous to apical two-chamber, fourchamber, and long-axis views were recorded with the probe lower in the right atrium. The right and left ventricles in the short-axis view could be imaged with the probe in the thoracic portion of the inferior vena cava. The mobility and motion of the aortic valve were well seen in the short-axis and modified longaxis views. The mitral valve could be imaged in modified two-chamber, four-chamber, and long-axis orientations. Flow dynamics could be ascertained with pulsed-wave and color flow Doppler imaging. Intracardiac echocardiography during aortic valvuloplasty. With the ultrasound transducer in the right

atrium, we were able to visualize the aortic valve, aortic root, and left ventricular outflow region in all animals. The guide wire was well seen as it was advanced through the valve, and similarly the balloon catheter could be imaged as it crossed the aortic valve. Images of the guide wire across the aortic valve and the catheter with a deflated balloon were obtained. During each of the 16 balloon inflations performed, the balloon appeared as a bright echo-dense mass across the valve and the borders of the balloon were well delineated (Figs. 2 and 3). This masswas no longer visible after deflation. We could clearly determine the precise positioning of the balloon and ascertain that the midportion of the balloon was across the aortic valve. The definition of the location of the balloon was more precise with echocardiographic than fluoroscopic imaging, inasmuch as the valve leaflets were visible with ultrasound imaging; the location of the valve by means of fluoroscopy was inferred from the cardiac sillouhette and the hemodynamic tracings. The valve morphology could be assessedimmediately after the simulated balloon valvuloplasty. There was no evidence of avulsion or perforation of a valve leaflet. Color flow Doppler imaging demonstrated the presence of aortic insufficiency after deflation in all instances (Fig. 4). No animal had severe aortic regurgitation demonstrated by color Doppler imaging or by a marked increase in pulse pressure. Intracardiac echocardiography during mitral valvulcplasty. As with aortic valvuloplasty, the guide wire

and the balloon catheter were visualized as they crossed the mitral valve into the left ventricle. Fig. 5 is an example of an image obtained during the procedure. Manipulations of the wire in the left atrium,

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5. Intracardiac echocardiographyduring experimental balloon mitral valvuloplasty. ILeft atrium (LA) is at topI of sector, left ventricle (LV) is toward bottom. Inflated balloon catheter @AL) is acrossmitral valve anulus.

Fig.

including unsuccessful attempts to position the wire across the valve, were well seen. The position of the balloon catheter in relation to the mitral leaflets was clearly evident from the echocardiographic images, but this was not the case with fluoroscopy alone. A total of eight inflations were carried out. The inflated balloon, appearing as a bright cylindrical hyperechoic structure, was seen across the mitral valve. Its position in relation to the valve and cardiac chambers was easily determined. In one dog the balloon burst, with dispersion of contrast echo signals freely into the left ventricle. In no instance did severe mitral regurgitation or a large “v” wave develop. Intracardiac echocardiography in acute pericardial effusion. Intracardiac echocardiography depicted the

epi-pericardial echo without any echo-free space in the baseline state. With the production of the pericardial effusion, an echo-free space surrounding the heart representing pericardial effusion was seen in all six dogs in which fluid was administered into the pericardial cavity. By employing multiple views,

fluid could be seen around the right and left ventricular free walls, the cardiac apex, and the right and left atria, as illustrated (Fig. 6). Effusion outside the ventricles was detectable in both the short-axis and “apical” orientations. In all instances even pericardial effusions smaller than 50 ml could be detected. The amount of fluid required to produce cardiac tamponade ranged from 100 to 180 cc. Pericardial effusion was seen before the development of tamponade in every instance. With production of tamponade, diastolic invagination of the right ventricular outflow region and proximal pulmonary artery region was seen in all dogs. Right atria1 collapse was seen in two dogs. DISCUSSION

Results of the present study demonstrate the potential utility of intracardiac echocardiography with a 5 MHz transducer during aortic and mitral valvuloplasty. With the use of a low-frequency transducer, an entire cardiac examination could be performed

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Fig. 6. Intracardiac echocardiographicrecordingsof experimentally produced pericardial effusion. Left, Image in control state of right ventricular inflow displaying right atrium (RA) and right ventricle (RV). Bright parietal pericardial layer is adjacent to right ventricular myocardium. Right, Sameview after introduction of saline solution into pericardial space. Pericardial effusion (PE), represented by echo-free

spaceoutside RA and RV, is now seen.

with the device in the right atrium. The aortic root and aortic valve, mitral valve, left atrium and left atria1 appendage, and interatrial septum were clearly visualized. Wire position in the aortic root, left ventricle, and left atrium could be determined before and after the aortic and mitral valves were crossed. The position of the deflated and inflated balloon catheters was seen in relation to the valve being “dilated.” This is a clear advantage over fluoroscopy, where the position of the balloon catheter in relation to the valve is frequently determined by inference from the cardiac sillouhette, the relationship to extracardiac structures, or the hemodynamic tracings. By using color Doppler imaging, we were able to assess the presence and severity of valvular regurgitation. Acute pericardial effusion was instantly detected, and signs of cardiac tamponade could be visualized. Comparison with other related work. Both transthoracic and transesophageal echocardiography have been used clinically during mitral valvuloplasty.i2, l3 These modes of imaging assisted with transeptal puncture, wire and catheter manipulation across the interatrial septum and mitral valve, balloon positioning across the mitral valve, and visualization of the atria1 septal defect after the procedure. Although transthoracic and transesophageal imaging methods are useful and are in fact used in some catheterization

laboratories during balloon valvuloplasty,

several

disadvantages have hindered their routine use during interventional procedures. Transthoracic echocardiography requires access to the chest wall and availability of optimal acoustic windows. The person performing the examination would need to do so without interfering with the sterile field. Space limitations

imposed by fluoroscopic equipment and the high degree of radiation exposure to the examiner also need to be considered. These cumbersome factors result in suboptimal imaging and disruption of the procedure. Transesophageal echocardiography avoids these problems; however, prolonged placement of the endoscopic transducer in an awake patient would be uncomfortable. Continuous transesophageal echocardiographic monitoring has been performed in a series of patients, but all of these patients received general anesthetic.14 It appears that intracardiac echocardiography could avoid these limitations. A probe passed into the right atrium from the femoral vein, if practical, would add little discomfort to the patient and avoid undue morbidity. The sterile field and the airway would be preserved. The person performing the valvuloplasty could easily position the ultrasound catheter for optimal image guidance. A low-frequency, intracardiac echocardiographic transducer with two-dimensional and Doppler echocardiographic capabilities is not available for use

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in patients. Other types of ultrasonic transducers have been used for intracardiac recording. Real-time M-mode echograms have been obtained from within the heart by other workers.r5p l6 This technique has never come into widespread use, probably because of the disadvantages of M-mode recording that became apparent when two-dimensional echocardiography became available. Investigators from this and other laboratories have used commercially available 20 MHz probes designed for intracavitary imaging of cardiac structures.17-20 Right- and left-sided heart structures, the pulmonary artery, and its branches have been visualized as part of routine catheterization procedures.15‘17 Pathologic conditions studied have included aortic and mitral stenosis, right atria1 masses,patent foramen ovale, anomalous pulmonary veins, and right ventricular dysfunction.17> I9 The ability of intracardiac ultrasonography to visualize the coronary sinus aided in the positioning of an ablation catheter into this structure in experimental and clinical settings.20 These catheters with 20 MHz transducers offer images with excellent resolution, but the depth of view is limited. Experience with these probes in humans and animals has demonstrated that entire cardiac chambers cannot be visualized.lg, 21 It is impossible to bring the left heart structures into view with the imaging catheter in the right heart, necessitating separate vascular entry if a comprehensive cardiac examination is to be performed. To image the entire heart from within the right atrium, as would be needed during valvuloplasty, a catheter bearing a low-frequency transducer needs to be developed. Critique of our study. This study was designed as a conceptual exploration to examine the potential applications of intracardiac echocardiography with lowfrequency ultrasound transducers. The results cannot be directly extrapolated to humans, inasmuch as ultrasound catheters bearing 5 MHz elements are not available for use in humans. The animals used all had normal valves; it is possible that thickened, fibrocalcific valves may alter the echocardiographic appearance of guide wires and balloon catheters as they cross these structures, but this has not been the case in reports on the use of transthoracic or transesophageal echocardiography during mitral valvuloplasty.12, l3 Inasmuch as the purpose of this study was to determine the feasibility of intracardiac echocardiography during valvuloplasty, no attempt was made to compare intracardiac echocardiography with transthoracic or transesophageal echocardiography. Such comparisons could not be extrapolated to use in humans because the relationship of the heart to both the esophagus and the chest wall are not the same in

dogs and humans, so imaging planes and quality would be expected to differ. The main advantage of recording from an intracardiac location is not that the images themselves would be better but that image aquisition would be possible without interfering with the interventional procedure, as in transesophageal echocardiography, and that such images could be obtained without causing undue discomfort to the patient as is possible if a prolonged transesophageal study is required. Another limitation of this study is the fact that we performed mitral valvuloplasty by introducing the catheter through a left atriotomy and did not use the transseptal technique. The larger size of the transducer we used prevented the passageof an additional catheter for the purpose of transseptal puncture from the inferior vena cava to the right atrium and maneuvering such a catheter within the right atrium itself. The ability of intracardiac ultrasound imaging to assist with transseptal puncture can be determined only by further investigation with smaller catheter-based probes. Concerning the detection of the complications of valvuloplasty, it is not surprising that pericardial effusion and valvular regurgitation could be visualized by means of intracardiac echocardiography. The advantage of intracardiac echocardiography would be the capability for instant detection of an effusion should it develop. Right atrial collapse, although detectable in two animals, could not be seen clearly in four others. This was probably because of the fact that the large transducer, which occupied most of the right atria1 chamber, was too close to the atria1 wall to be able to display the free wall consistently. What is important clinically, however, is the detection of a new pericardial effusion in a subject with hemodynamic compromise; this purpose was accomplished by intracardiac echocardiographic imaging in our experimental study. It is also not surprising that valvular insufficiency could be detected by intracardiac echocardiography. No attempt was made to validate the presence or degree of regurgitation by other techniques. Multiple studies that use either transthoracic or transesophageal echocardiography have determined color flow Doppler imaging to be an accurate technique for the quantification of aortic and mitral regurgitation.22-24 We have assumed that the same is true for intracardiac echocardiography. Validation studies are required before this technique becomes clinically applicable. Clinical implications. Percutaneous balloon valvuloplasty of the mitral and aortic valves are accepted clinical procedures in selected patients.25-32 Intracardiac echocardiography has the potential to assist

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greatly during these procedures. Morphology and motion of the valve leaflets, orifice size, and the presence and severity of regurgitation before and after the procedure could be determined. Once refinements in this technology have been made, such as the development of low-frequency, catheter-based probes, these imaging devices could be introduced from the femoral vein and controlled by the operator with little if any additional discomfort to the patient. Potential applications, as we have shown in this study, include determination of valvular morphology and mobility, aiding in balloon catheter placement, detection of valvular insufficiency after valvuloplasty, and identification of cardiac perforation. Further research, including miniaturization of the transducer, and perhaps incorporation of the ultrasound transducer into a balloon catheter will make it possible for intracardiac echocardiography to be available for use in humans in the future.

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REFERENCES

1. Pandian NG, Kreis A, Brockway B, Isner JM, Sachoroff A, Boleza E, Caro R, Muller D. Ultrasound angioscopy: real-time, two-dimensional, intraluminal ultrasound imaging of blood vessels. Am J Cardiol 1988;62:493-4. 2. Pandian NG, Kreis A, O’Donnell T. Intravascular ultrasound angioscopic estimation of arterial stenosis. J Am Sot Echocardiogr 1989;2:390-7. 3. Hodgson JM, Graham SP, Savakus AD, Dame SG, Stephens DN, Dhillon PS, Brands D, Sheehan H, Eberle MJ. Clinical percutaneous imaging of coronary anatomy using an over-thewire ultrasound catheter system. Int J Card Imaging 1989; 4:187-93. 4. Tobis JM, Mallery JA, Gessert J, Griffith J, Mahon D, Bessen M, Moriuchi M, McLeay L, McRae M, Henry WL. Intravascular ultrasound cross-sectional arterial imaging before and after balloon angioplasty in vitro. Circulation 1989;80:873-82. 5. Yock PG, Linker DT, Angelsen BAJ. Two-dimensional intravascular ultrasound: technical development and initial clinical experience. J Am Sot Echocardiogr 1989;2:296-304. 6. Weintraub A, Schwartz S, Pandian N. How reliable are intravascular ultrasound and fiberoptic angioscopy in the assessment of the presence and duration of intra-arterial thrombosis in atheromatous vessels with complex plaques [Abstract]? J Am Co11 Cardiol 1990;15(suppl A):17A. 7. Schwartz SL, Pandian NG, Kusay BS, Kumar R, Weintraub A, Katz SE, Aronovitz M. Realtime intracardiac two-dimensional echocardiography: an experimental study of in vivo feasibility, imaging planes, and echocardiographic anatomy. Echocardiography-1990;7:443-55. 8. Seward JB, Khandheria BK, McGregor CGA, Locke TJ, Tajik AJ. Transvascular and intracardiac 2-dimensional echocardiography. Echocardiography 1990;7:457-64. 9. Schwartz SL. Kusav BS. Pandian NG. Aronovitz M. Konstam MA, Salem D. Utility of in vivo, intracardiac 2-dimensional echocardiography in the assessment of myocardial risk area and myocardial dyssynergy during coronary occlusion and reperfusion [Abstract]. Circulation 1989;8O(suppl 2):11-374. 10. Valdes-Cruz LM, Sideris E, Sahn DJ, Murillo-Olivas A, Knudson 0, Omoto R, Kyo S, Gulde R. Transvascular intracardiac applications of a miniaturized phase-array ultrasonic endoscope: initial experience with intracardiac imaging in piglets. Circulation 1991;83:1023-7. 11. Herrmann HC, Kleaveland JP, Hill JA, Cowley MJ, Margolis JR, Nocero MA, Zalewski A, Pepine CJ. The M-Heart percu-

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taneous balloon mitral valvuloplasty registry: initial results and early follow-up. J Am Co11 Cardiol 1990;15:1221-6. Pandian NG, Isner JM, Hougen TJ, Desnoyers MR, McInerney K, Salem DN. Percutaneous balloon valvuloplasty of mitral stenosis aided by cardiac ultrasound. Am J Cardiol 1987; 59390-l. Kronzon I, Tunick PA, Schwinger ME, Slater J, Glassman E. Transesophageal echocardiography during percutaneous mitral valvulonlastv. J Am Sot Echocardioar 1989:2:380-5. Jaarsma W; Visseer CA, Suttorp MJ, Haagen FDH, Ernst SMPG. Transesophageal echocardiography during percutaneous balloon mitral valvuloplasty. J Am Sot Echocardiogr 1990;3:384-91. Conetta DA, Christie LG, Pepine CJ, Nichols WW, Conti CR. Intracardiac M-mode echocardiography for continuous left ventricular monitoring: method and potential application. Cathet Cardiovasc Diagn 1979;5:135-43. Glassman E, Kronzon I. Transvenous intracardiac echocardiography. Am J Cardiol 1981;47:1255-9. Weintraub A, Pandian N, Salem D, Schwartz S, Konstam M, Millen V. Realtime intracardiac two-dimensional echocardiographs in the catheterization laboratory in humans ]Ab&-act]. J Am Co11 Cardiol 1990;15(suppl k):16A. Pandian NG. Weintraub A. Kreis A. Schwartz SL. Konstam MA, Salem DN. Intracardiac, intravascular, two-dimensional high frequency ultrasound imaging of pulmonary artery and its branches in humans and animals. Circulation 1990;81:200712. Weintraub A, Pandian N, Sanzobrino BW, Pachucki DQ, Katz S, Schwartz S, Konstam M, Salem D, McKay RG, Gillam LD. Intravascular and intracardiac ultrasound imaging of the heart and great vessels: practicality, utility, and safety-experience in 100 patients [Abstract]. Circulation 1990;82(suppl 3):111-441. Berns E, Mitchel J, Mehran R, Theriot P, Iyenger J, Kimura Y, McKay R, Gillam L. Ablating catheter placement under direct visualization with the intravascular ultrasound probe: a potential aid to ablative therapy of arrhythmias [Abstract]. J Am Co11 Cardiol 1990;15(suppl A):lSA. Schwartz S, Kusay B, Pandian N, Kumar R, Weintraub A, Katz S, Aronovitz M, Salem D. In vivo intracardiac 2-D echocardiography: effects of transducer frequency, imaging approaches and comparison with fiberoptic angioscopy [Abstractl. J Am Co11 Cardiol 1990:15(suppl A):29A. Helmke F, Nanda NC, Hsuing MC; Sbto B, Adey CK, Goyal RG, Gatewood Jr RP. Color Doppler assessment of mitral regurgitation with orthogonal planes. Circulation 1987;75:17583 -_. Perry GJ, Helmcke F, Nanda NC, Byard C, Soto B. Evaluation of aortic insufficiency by Doppler color flow mapping. J Am Co11 Cardiol 1987;9:952-9. Yoshida K, Yoshikawa J, Yamaura Y, Hozumi T, Akasaka T, Fukaya T. Assessment of mitral regurgitation by biplane transesophageal color Doppler flow mapping. Circulation 1990;82:1121-6. Cribier A, Savin T, Berland J, Rocha P, Mechmeche R, Saoudi N, Behar P, Letac B. Percutaneous transluminal balloon valvuloplasty of adult aortic stenosis: report of 92 cases. J Am Co11 Cardiol 1987;9:381-6. Isner JM, Salem DN, Desnoyers MR, Hougen T, Mackey WC, Pandian NG, Eichorn EJ, Konstam MA, Levine HJ. Treatment of calcific aortic stenosis by balloon valvuloplasty. Am J Cardiol 1987;59:313-7. Lock JE, Khalilullah M, Shrivastava S, Bahl V, Keane JF. Percutaneous catheter commissurotomv in rheumatic mitral stenosis. N Engl J Med 1985;313:515-8: Inoue K. Owaki T. Nakamura T. Kitamura F. Mivamoto N. Clinical application of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 1984;87:394402. Vahanian A, Michel PL, Cormier B, Vitoux B, Michel X, Slama M, Sarano LE, Trabelsi S, Ismail MB, Acar J. Results

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of percutaneous mitral commissurotomy in 200 patients. Am J Cardiol 1989;63:847-52. 30. McKay CR, Kawanihi DT, Kotleswski A, Parise K, OdomMaryon T, Gonzalez A, Reid CL, Rahimtoola SH. Improvement in exercise capacity and exercise hemodynamics three months after double-balloon, catheter balloon valvuloplasty treatment of patients with symptomatic mitral stenosis. Circulation 1988;77:1013-21.

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Palacios IF, Block PC, Wilkins GT, Weyman AE. Follow up of patients undergoing percutaneous mitral balloon valvotomy. Circulation 198$79:573-g. 32. Safian RD, Berman AD, Diver DJ, McKay LL, Come PC, Riley MF, Warren SE, Cunningham MJ, Wyman M, Weinstein JS, Grossman W, McKay RG. Balloon aortic valvuloplasty in 170 consecutive patients. N Engl J Med 1988;319:125-30. 31.

of native coarctation and young adults

of the

Balloon angioplasty of native coarctation of the aorta was performed in 35 consecutive adolescents and young adults, aged 14 to 37 years (mean 22.6 + 7.1). Twenty-eight (80%) patients had isolated discrete coarctation, six (17.1%) had tubular hypoplasia of the aortic isthmus, and one (2.9%) had hypoplasia of the postcoarctation aorta. The peak systolic pressure gradient decreased from 78.5 -t 23.9 to 15.7 f 11.6 mm Hg (p < O.OOl), and the mean coarctation diameter increased from 4.7 f 2.4 to 13.1 + 2.7 mm (p < 0.001) immediately after angioplasty. Patients with discrete-type coarctation had significantly less residual gradient than patients with long-segment tubular coarctation (12.3 + 10.7 vs 27.2 + 6.6 mm Hg, p < 0.01). On recatheterization and angiography in 26 patients at 12.6 f 1.5 months after dilatation, there was no significant change in gradient (15.5 & 13.3 mm Hg) and diameter (13.1 -t 1.8 mm) from the immediate postangioplasty results. However, two patients had an increase in gradient and three had small aortic aneurysms wlth no change in appearance on restudy after 2 years. After 3 to 67 months’ (mean 32.7 + 19.2) follow-up, all patients showed continued clinical improvement. Hypertension was relieved in 37.5% (12132) and improved in 59.4% (19132). Our experience suggests that balloon angloplasty of native aortic coarctatlon in adolescents and young adults is safe and highly effective with sustained improvement on intermediate-term follow-up. (AM HEART J lgg2;123:674.)

Sanjay Tyagi, MD, DM, Ramesh Arora, MD, DM, Upkar A. Kaul, MD, DM, Kamal K. Sethi, MD, DM, Daljeet S. Gambhir, MD, DM, and Mohd. Khalilullah, MD, DM. New Delhi, India

Since the initial report of balloon angioplasty for coarctation of the aorta in 1982,l several short-2-8 and a few intermediate-termg-17 studies have been carried out to determine the efficacy of this technique. Most of these studies have been in infants and children. There are only a few brief accounts of balloon angioplasty in adolescents and young adults.5, ls20 Reports of surgical correction have shown that hospital mortality, recoarctation, persistent hypertension, and

From Received

the Department for publication

of Cardiology, April

Reprint requests: Sanjay Tyagi, Cardiology, G. B. Pant Hospital, 4/l/34421

674

G. B. Pent

29, 1991;

accepted

Hospital. Aug.

1, 1991.

DM, Associate Professor, Department New Delhi 110 002, India.

of

cerebral hemorrhage are affected by the age at intervention.21-23 In this study, the largest series of patients of this age group, we report our immediate and intermediate-term follow-up results of percutaneous balloon dilatation for relief of native aortic coarctation in adolescents and young adults. METHODS Between July 1985 and December 1990, a total of 35 consecutive patients (29 males and 6 females), ranging in age from 14 to 37 years (mean 22.6 k 7.1), with a diagnosis of native aortic coarctation based on results of clinical examination and two-dimensional and pulsed Doppler echocardiography, underwent cardiac catheterization and aortography. Under local anesthesia, percutaneous retrograde femoral artery catheterization was performed by the