Mohsin Alam

The role of transesophageal echocardiography in identifying anomalous coronary arteries.

BackgroundThe study objective was to evaluate the role of transesophageal echocardiography in identifying the origin of anomalous coronary arteries and confirming their course in relation to the great vessels. The diagnosis of coronary anomalies is made by angiography. The anomalous left main artery with a course between the pulmonary artery and the aorta has been associated with myocardial infarction and sudden death. The course of these anomalous coronary arteries is difficult to demonstrate by angiography alone. Methods and ResultsNine patients with angiographically confirmed anomalous coronary arteries were studied by transesophageal echocardiography with color flow Doppler. The abnormal origin of the anomalous coronary arteries was confirmed by transesophageal echocardiography in all nine patients. In four patients, the left main coronary artery originated from the right sinus of Valsalva. In all of these patients, transesophageal echocardiography demonstrated the course of the anomalous left main coronary artery between the aorta and pulmonary artery better than angiography. Other anomalies that were visualized included two patients with origin of the right coronary arteries from the left aortic sinus, one patient with origin of the left anterior descending from the right sinus, one patient with origin of circumflex from the right sinus, and one patient with origin of the left main coronary artery from the pulmonary artery. ConclusionsTransesophageal echocardiography is a useful noninvasive test for diagnosing anomalous origin of the coronary arteries. Furthermore, it is a valuable adjunct to angiography in demonstrating the abnormal course of the left main coronary artery interposed between the aorta and the pulmonary artery, a potentially life-threatening entity.

Spontaneous Degeneration of Porcine Bioprosthetic Valves

From October, 1971, to October, 1979, 490 patients with 560 porcine bioprosthetic valves were discharged from the hospital. During these 8 years, 23 valves were removed because of failure due to spontaneous degeneration. Bioprosthetic valve survival without degeneration was at 4 years, 98.9% +/- 86 (standard error); at 5 years, 96.4% +/- 1.3; at 6 years, 90.8% +/- 2.4; and at 7 years, 84.2% +/- 3.7. There was no difference in degeneration observed with regard to sex, valve position, or whether the valves were rinsed with antibiotics prior to implantation. There was an increase in degeneration in patients 35 years old and younger compared with those more than 35 years old (p = 0.0001). Valve failure was gradual, and valve changes were noted by echocardiogram and phonocardiogram prior to actual failure. Specific factors leading to degeneration require further investigation.

Echocardiographic evaluation of left ventricular function during coronary artery angioplasty

Balloon occlusion of a stenotic coronary artery during percutaneous coronary artery angioplasty provides a unique opportunity to study the effect of acute myocardial ischemia on left ventricular (LV) function. Simultaneous M-mode and 2-dimensional (2-D) echocardiograms and a 6-lead electrocardiogram were recorded during 20 episodes of coronary artery occlusion and release in 12 patients. No patient had previous myocardial infarction and all had normal LV function by angiography. All patients had isolated single coronary artery disease, with left anterior descending stenosis in 8 and right coronary stenosis in 4. In 18 of 20 episodes (90%), M-mode echocardiography during balloon occlusion revealed a significant (p less than 0.001) decrease in LV systolic, diastolic and percent systolic wall thickness; systolic excursion; systolic and diastolic endocardial velocities; and fractional shortening. These changes were observed in the area of the ventricular septum in patients with left anterior descending occlusion and posteroinferior wall in those with right coronary artery occlusion. Two-dimensional echocardiography revealed varying degrees of hypokinesia, akinesia and dyskinesia during balloon occlusion in 18 instances. The echocardiographic changes were observed within 15 to 20 seconds of balloon occlusion and resolved 10 to 20 seconds after balloon deflation. All patients who had echocardiographic changes during balloon occlusion also had concomitant electrocardiographic (ECG) ST-segment elevation, whereas 2 patients with normal LV function had no ECG changes. Both of these patients had profuse collateral blood supply to the stenotic coronary artery. The echocardiographic and ECG abnormalities increased proportionately to the length of balloon occlusion. This study confirms previous animal and recent human studies of transient LV dysfunction during coronary occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

The Porcine Bioprosthetic Heart Valve: Experience at 15 Years

The porcine bioprosthetic valve has been in use at Henry Ford Hospital since 1971. In this review, 980 patients with 1,081 porcine bioprosthetic valves were examined from 1 month to 16.4 years after implantation with a 99% complete follow-up. Patient survival was 59% +/- 2.2% (+/- standard error of the mean) at 10 years and 38% +/- 4.0% at 15 years. Factors associated with decreased survival after hospital discharge were age greater than 35 years and New York Heart Association functional class IV. Freedom from thromboembolism was 92% +/- 1.2% at 10 years and 89% +/- 3.2% at 15 years. Freedom from endocarditis was 93% +/- 1.2% at 10 years and 92% +/- 1.3% at 15 years. Freedom from structural valve degeneration for all valves was 71% +/- 2.6% at 10 years and 31% +/- 5.6% at 15 years. Factors associated with increased risk of structural valve degeneration were age younger than 35 years, female sex, and preoperative cardiac index greater than 2 L/min/m2. Among a total of 172 patients undergoing removal of a degenerated valve, mortality was 12.5%, and significant risk factors for death at reoperation were emergency operation and functional class IV. Experience with the porcine bioprosthetic valve after 15 years suggests that its use be confined to older patients or patients with a contraindication of anticoagulation.

Doppler and echocardiographic features of normal and dysfunctioning bioprosthetic valves

Echocardiographic and Doppler studies were performed on 183 clinically normal and 58 severely dysfunctioning bioprosthetic mitral, aortic and tricuspid valves. The valve dysfunction resulted from spontaneous cusp degeneration in 49 instances and from paravalvular regurgitation in 9. The pulsed Doppler study demonstrated regurgitant flow in 36 (92%) of 39 regurgitant valves and 8 (90%) of 9 paravalvular regurgitant valves. Diagnostic echocardiographic features were present in only 51 and 10% of the patients, respectively. Although the Doppler regurgitant jet was peripheral in seven of the nine patients with paravalvular regurgitation, it was not possible to differentiate these patients from those who had valve degeneration and cusp tear at the periphery of the valve ring. Eight patients presented with a musical holosystolic murmur of mitral insufficiency. In all eight there was a characteristic honking intonation on the audio signal and a striated shuddering appearance on the video Doppler signal. Ten stenotic mitral bioprosthetic valves (less than or equal to 1.1 cm2 valve orifice) were identified by Doppler study. Diagnostic echocardiographic features were present in only two of these patients. The Doppler-derived valve orifice dimension correlated well (r = 0.83) with cardiac catheterization values. Fourteen asymptomatic or minimally symptomatic patients had echocardiographically thickened mitral cusps (greater than or equal to 3 mm). These patients had a significantly (p less than 0.0001) smaller valve area as compared with normal control valves, and during 4 to 24 months of follow-up, five of these patients developed severe valve regurgitation or stenosis. Doppler ultrasound is more sensitive than echocardiography in diagnosing bioprosthetic valve stenosis and regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal echocardiography in critical care units: Henry ford hospital experience and review of the literature

Transthoracic echocardiography is of limited value in intensive care units primarily because of mechanical ventilators, surgical wounds, and the inability to position the patient to his left side. Imaging from the transesophageal window overcomes these problems, resulting in good-quality study in these patients subsets. We performed both transthoracic and transesophageal echocardiography with color-flow Doppler tests in 121 patients in various critical care units. The transesophageal ultrasound test was valuable in identifying patients with suspected left-sided native and prosthetic valve vegetations, prosthetic mitral but not aortic valve regurgitation, native mitral and aortic valve pathoogy, and aortic dissection and in determining cardiac etiology of systemic emboli, hypotension, hypoxia, and heart failure. Based on transesophageal echocardiographic findings, additional information was provided in 38 (32%) patients, resulting in appropriate surgery in 22 instances. In conclusion, transesophageal echocardiography is a useful tool in evaluating critically ill patients.

Transesophageal Echocardiographic Evaluation of Left Atrial Mass Lesions

Transesophageal echocardiography with color flow Doppler studies was performed on 12 consecutive patients who had left atrial mass identified by transthoracic echocardiography. In two patients with atrial myxoma, transesophageal study identified the tumor by its attachment to the atrial septum. In all instances, the tumors were larger and more mobile by transesophageal study and influenced the decision to operate early on an asymptomatic patient. In six instances the masses in the atria were deemed to be thrombi because of associated spontaneous echo contrast, location in the left atrial appendage, mitral valvular disease or prosthesis, atrial fibrillation, congestive heart failure, and enlarged left atrial chamber. In two patients the left atrial masses on transesophageal imaging were large vegetations attached to the mitral valve with ruptured chordae tendineae. In two patients, because of superior quality images obtained by transesophageal imaging, the atrial mass lesions were deemed to be a prominent muscle band between the left atrial appendage and left upper pulmonary vein. In conclusion, transesophageal echocardiography is superior to transthoracic imaging in elucidating the cause and significance of atrial mass lesions and helps in guiding appropriate therapy.

M mode and two dimensional echocardiographic features of porcine valve dysfunction

The echocardiographic features are presented of degeneration of nine glutaraldehyde-fixed porcine xenograft valves implanted in eight patients. These features occurred 11 to 68 months after implantation and were correlated with surgical and necropsy findings. Acute bacterial endocarditis was present in two patients, and had been successfully treated medically in three other patients 47 to 52 months before valve degeneration was recognized. The valve was severely thickened in four patients and in two of the four the thickening was associated with a significant hemodynamic transvalve gradient. M mode echocardiography demonstrated increased thickness and loss of the cusp detail. In five patients severe regurgitation due to a tear in one or more cusps developed in the the valve in the mitral position. M mode echocardiography in all five patients revealed on the valve systolic or diastolic fluttering echoes, or both. The two dimensional echocardiogram demonstrated thickened cusps with systolic protrusion of the leaflets into the left atrium. Both modes of echocardiography were of valve in identifying degeneration of the porcine xenograft valve.

Pitfalls in the Echocardiographic Diagnosis of Intracardiac and Extracardiac Masses

Transthoracic and transesophageal two‐dimensional (2‐D) echocardiography remain the procedures of choice for evaluating cardiac mass lesions. Potential errors in diagnosis can be made, however, if the mass lesions size, shape, mobility, and attachment to other cardiac structures are not clearly delineated. Usually a left atrial myxoma arises from the interatrial septum at the level of the fossa ovalis. Pitfalls in diagnosis occur when the tumor size is very small, or its attachment site is atypical or ill‐defined. Atrial thrombi classically reside in an atrial appendage, but can also form in the body of the left atrium. The presence of atrial fibrillation rhythm, enlarged atrial chamber, prosthetic mitral/tricuspid valves, stenotic mitral/tricuspid valves, low cardiac output state, and spontaneous atrial contrast echoes are all features that favor the mass in question being a thrombus. Ventricular thrombi usually occur with poorly functioning ventricles. The diagnosis of ventricular thrombus should be made with great caution if the systolic function is normal, or if the mass has a band or thread‐like appearance. A thorough knowledge of normal anatomical variants that can mimic pathological lesions is also important for reaching a correct diagnosis. Last but not least, as in all testing modalities, the patients clinical picture should be correlated with the echocardiographic findings.

Transesophageal Echocardiographic Evaluation of Right Atrial Mass Lesions

Transesophageal echocardiography with color flow Doppler studies was performed on 10 consecutive patients who had right atrial masses identified by transthoracic echocardiography. In one patient with right atrial myxoma, transesophageal study identified the tumor by its attachment to the atrial septum and ruled out the transthoracic finding of possible additional tumor mass in the right ventricle. In two instances the mass in the atria were deemed to be thrombi because of lack of attachment to the atrial septum, atrial fibrillation, and enlarged right atrial chambers. In all patients, the thrombi appeared larger by transesophageal study and was associated in one instance with atrial septal defect. The atrial septal defect was not identified by the transthoracic study and probably accounted for stroke of the patient through paradoxical emboli. In six patients, because of superior quality images rendered by transesophageal imaging, the right atrial mass lesions were deemed to be anatomic variants, which included prominent eustachian valves, remnants of Chiari network, and thickened atrial septum. We concluded that transesophageal echocardiography is superior to transthoracic imaging in elucidating the cause and significance of right atrial mass lesions and that it helps in guiding appropriate therapy.