Malfunction of mitral ball valve prosthesis due to thrombus. Report of 2 cases with notes on early clinical diagnosis

Echocardiography in mitral valve disease: a review

Echocardiographic evaluation of the mitral valve has attracted much attention and generated much discussion since its beginnings, some thirty years ago. Echocardiography affords the physician a detailed assessment of mitral valve integrity unequalled by any other non-invasive test. Aside from the normal appearance of the valve, a variety of pathological conditions have been studied in detail; mitral stenosis was the first and over the years the state-of-the-art has evolved from simply looking at the EF slope as an indicator of severity to the accurate quantification utilizing planimetry and 'pressure half-time.' Mitral regurgitation, although not as well quantified as mitral stenosis, can be detected and its etiology usually determined. Mitral valve prolapse may easily be overdiagnosed by echocardiography, however together with auscultation, ultrasound remains the best way to evaluate this common condition. Echocardiography is also invaluable in the evaluation of endocarditis and prosthetic mitral valves.

Doppler echocardiography in the study of patients with mitral disc valve prostheses

A combination of M mode and Doppler echocardiography was used to study patients with mitral disc valve prostheses. The probe used in these investigations consisted of a circular Doppler crystal mounted around the M mode crystal in the same plane. Because of the strong echoes produced by the prosthesis the transducer (probe) could be angled for optimum Doppler signals without losing the M mode echocardiographic recording of the prosthesis. With this equipment mean and maximum blood velocities and Doppler amplitude signals could be measured simultaneously with M mode echocardiography. A depth indication line in the M mode recording ensured that the Doppler signal was recorded in the region of interest. The Doppler ultrasound technique was also used separately in both the pulsed wave and the continuous wave mode. The data show the usefulness of this technique in patients with normally functioning valve prostheses and in three patients with valve malfunction due to thrombus formation. The data in the latter three cases seem to indicate that the Doppler technique provides valuable information in addition to that obtained by M mode echocardiography in recognising mitral valve prosthetic malfunction.

Echocardiographic evaluation of porcine bioprosthetic valves: experience with 309 normal and 59 dysfunctioning valves

To determine the clinical value of echocardiographic evaluation of porcine bioprosthetic valves, the findings in all patients who had porcine bioprosthetic valve replacement and adequate quality echocardiographic studies from 1978 to 1982 were analyzed. The study includes 309 normal and 59 dysfunctioning valves. Valve dysfunction resulted from spontaneous cusp degeneration in 39 (34 valve regurgitations, 5 stenoses), infective endocarditis in 12, paravalvular regurgitation in 5, regurgitation of redundant cusps, mitral valve thrombi, and aortic stent stenosis in 3 others. Echocardiographic findings were correlated with gross surgical pathologic or autopsy findings in 45 of the 59 dysfunctioning valves. Echocardiographic abnormalities were demonstrated in 41 of 59 (69%) dysfunctioning valves. A systolic mitral or diastolic aortic valve flutter was diagnostic of a regurgitant valve caused by a torn or unsupported cusp margin and was observed in 28 of 34 (82%) regurgitant valves with no false-positive studies. Echocardiographic cusp thickness of greater than or equal to 3 mm correctly identified all regurgitant and stenotic valves with gross anatomic evidence of localized or generalized cusp thickening or calcific deposits. Echocardiographic valve abnormalities were observed in only 4 of 12 patients with infective endocarditis and in 1 of 5 with paravalvular regurgitation. Thus, echocardiography provides important information regarding the function of porcine bioprosthetic valves and is of value in the decision to replace these valves, especially when dysfunction is due to spontaneous cuspal degeneration. Echocardiography is neither sensitive nor specific in patients with infective endocarditis and paravalvular regurgitation.

Noninvasive evaluation of normal and abnormal prosthetic valve function

Noninvasive techniques are helpful in evaluating the function of mechanical prostheses and tissue valves. Combined phonocardiography and M-mode echocardiography together with cinefluoroscopy are the most useful noninvasive techniques in differentiating normal from abnormal metallic prosthetic valve function. The intensity of the opening and closing clicks and associated murmurs will depend on the type of prosthetic valve, the heart rate and rhythm and the underlying hemodynamic status. Arrhythmias or conduction disturbances, or both, may produce motion patterns that mimic some of the echocardiographic signs of malfunctioning prosthetic valves. Differentiation of thrombus formation or tissue ingrowth from paravalvular regurgitation or dehiscence is possible by noninvasive techniques. Disc variance, a potentially serious and lethal problem with the older Beall valves, can be readily detected by cinefluoroscopy and echophonocardiography. With regard to bioprosthetic valves, two-dimensional echocardiography is superior to M-mode echocardiography in detecting primary valve failure. In addition, detection of vegetations, valve alignment and ring and individual leaflet motion can be best accomplished by two-dimensional echocardiography. Of greater importance is the patient serving as his or her own control in the follow-up assessment of prosthetic valve function by noninvasive techniques.

Prosthetic mitral valve motion during cardiac dysrhythmias as determined by echocardiography

To assess the changes and physiologic mechanisms of prosthetic valve motion during cardiac dysrhythmias as well as the role of atrial systole in the closure of the mitral valve, M-mode echocardiography was performed in 36 patients with normally functioning prosthetic mitral valves (Björk-Shiley, Starr-Edwards, and Beall valve). Premature closure of the prosthetic mitral valve in diastole with a "sharp" closing motion was seen during first-degree atrioventricular block, atrial fibrillation with ventricular rates less than 60 beats/min, and atrial flutter. A "rounded" premature valve closure due to atrial systole was seen during atrial tachycardia and complete heart block. Atrial systole initiates a closing motion of the prosthetic mitral valve at end-diastole, and ventricular systole completes this closure during normal sinus rhythm. When first-degree atrioventricular block is present, atrial systole alone completes this closure before ventricular contraction. Atrial contraction alone also can effectively close the prosthetic mitral valve during atrial flutter and atrial tachycardia. Other factors (such as left ventricular diastolic volume) may play a role in the effective closure of the prosthetic mitral valve during atrial fibrillation with slow ventricular rates and complete heart block. These findings must be considered in the echocardiographic evaluation of suspected malfunctioning prosthetic mitral valves. A baseline postoperative echocardiogram after prosthesis insertion is important for future evaluation when clinically indicated.

Bioengineering aspects of heart valve replacement

Biomedical engineering inputs have been important in the design, development and testing of substitute heart valves as well as in the pre- and post-operative management of patients with cardiac valve disease. This paper is a review of heart valve replacement whose goal is the enhancement of future bioengineering contributions. We review the approach to the patient with valvular heart disease, and the sources of early and late postoperative pathology with emphasis on complications of the prostheses used. Major significant problem areas relate to the noninvasive evaluation of cardiovascular function (both before and after surgery), device design, hemodynamics, and the need for thromboresistant and durable materials.

An unusual case of Bjork-Shiley mitral valve dysfunction corrected nonsurgically

A case of Bjork-Shiley mitral valve dysfunction is presented. The patient has not responded to anticoagulant therapy and had hypotension, dyspnea, chest pain, and a pulse deficit but normal sinus rhythm. Simultaneous echocardiogram, ECG, and arterial pulse tracing were used as noninvasive means of monitoring. Nonsurgical correction of a clinical emergency restored the patient to prior normal baseline cardiovascular function. This case illustrates the possibility of restoring normal prosthetic function by supporting the patient medically while undertaking diagnostic testing and arranging surgical intervention. To our knowledge, this is the first reported case of a malfunctioning Bjork-Shiley mitral valve corrected without surgery.

Echocardiographic evaluation of the St. Jude medical prosthetic valve

M-mode and two-dimensional echocardiographic studies were performed on 19 patients with 25 normally functioning St. Jude Medical prosthetic cardiac valves, in an attempt to define the normal echocardiographic appearance of this new cardiac prosthesis. Satisfactory M-mode echocardiograms were obtained in 17 of the 19 patients, and satisfactory two-dimensional studies were obtained in all. M-mode measurements included the diameter of the orifice ring, leaflet separation, and the opening and closing slopes of the leaflets. The values obtained compared favorably with direct measurements from the prosthesis and were reasonably reproducible. Two-dimensional imaging revealed characteristic systolic and diastolic patterns and provided direct visualization of valvular motion. Echocardiographic evaluation of the prosthesis can be facilitated if it is positioned at implantation so that the open leaflets are perpendicular to the echocardiographic plane of the long axis of the ventricle.

Fibrinolytic treatment of thrombus on prosthetic heart valves

Fibrinolytic agents were administered for 13 episodes of thrombus formation on mitral or aortic valvar prostheses in 12 patients. The most common presenting features were pulmonary oedema (six cases) or arterial emboli (six cases). The diagnosis of thrombus formation was made by phonocardiography on the following criteria: (a) modifications of the prosthetic sounds (12 cases), (b) appearance of a valvar obstructive syndrome (10 cases). The treatment consisted of streptokinase (100 000 units/h after a loading dose, seven cases) or urokinase using either low doses (75 000 or 112 500 units/h, three cases) or moderate doses (150 000 units/h, three cases) for one to four days. Immediate complete regression of clinical and phonocardiographic anomalies was seen in eight cases. Incomplete improvement was seen in two patients, leading to operation: this was unsuccessful in one patient who had surgery on the third day, and was successful in the other on the 75th day. There were three failures leading to successful reoperative procedures in two patients and to an early death in the third patient suffering from acute myocardial infarction. One non-fatal haemopericardium was observed in a patient treated with streptokinase. No important side effect was noted during delivery in a pregnant woman. During subsequent follow-up, a recurrent episode of thrombus formation was observed in one patient, treated by fibrinolytic therapy with success. One patient had an operation for a valve replacement six months after fibrinolytic treatment because of non-thrombotic valvar dysfunction; the outcome was fatal. Six patients are alive and in good condition, with a follow-up of six months to five years.

Noninvasive diagnosis of mitral prosthesis malfunction

We describe the utilization of echocardiography and phonocardiography in the diagnosis of malfunction of the Smeloff-Cutter mitral prosthesis in a patient in whom corrective surgery was subsequently performed without the necessity of cardiac catheterization studies. The noninvasive studies also delineated prosthesis malfunction as the etiology of pulsus alternans, noted clinically in this patient.

Echo-phonocardiographic evaluation of obstruction of prosthetic mitral valve

Echo-phonocardiograms of 64 patients with multiple types of prosthetic mitral valves (PMV) were evaluated. Six patients demonstrated findings suggesting valve obstruction: four had surgical confirmation of prosthetic obstruction, one reduced cardiac output and pulmonary hypertension but no prosthetic dysfunction at surgery, and one is asymptomatic. Three of four patients with confirmed obstruction had variable second sound to opening click intervals (A2-MO) with interrupted disc opening; two had interrupted disc closure with split closing clicks and three of four had reduced diastolic closure rate. In 58 clinically well patients with PMV, cycle-to-cycle A2-MO varied little: 0-10 msec in sinus rhythm and 10-25 msec in atrial fibrillation. Diastolic closure rates of five different types of PMV were similar: 21.6 mm/sec, (range 14-49). No patient had interrupted opening, closing or multiple closing clicks. Thus, delayed PMV opening or closure, altered A2-MO interval and double closing clicks are highly useful in detecting patients with obstruction of a variety of mitral prostheses.

Reoperation for dysfunction of the Björk-Shiley mitral disc prosthesis: report of eight cases

Of 193 patients with Björk-Shiley mitral valve prostheses, replacement was necessary in 8 (4.1%). The reasons for reoperation were: detachment (4), thrombosis (1), technical error (1), and late disc entrapment (2). Five of these patients died (62.5%), the death being directly related to the need for urgent operation because of low cardiac output. We recommend avoiding the use of the larger sized Björk-Shiley prostheses, since striking of the disc against the ventricle wall, probably consequent to postoperative decrease in heart size, may appear even 1 year after implantation of the prosthesis. An early diagnosis and early reoperation offer these patients a much more favorable prognosis.

Malfunction of Björk-Shiley valve prosthesis in tricuspid position

Eight months after triple valve replacement with Björk-Shiley tilting disc valves a patient developed symptoms and signs suggesting malfunction of the prosthesis in the tricuspid position. This was confirmed by echocardiography and angiocardiography, and at operation thedisc of the prosthesis was found to be stuck half-open by fibrin and clot. A further 11 patients with the same tupe of prosthesis in the triscupid position were then studied by phonocardiography and echocardiography. In one of these the prosthesis was found to be stuck and this was confirmed by angiocardiography and surgery. These 2 cases are reported in detail and the findings in the other 10 are discussed. The implications of this high incidence of malfunction of the Björk-Shiley prosthesis in the tricuspid position are considered. Echocardiography appears to be essential in the follow-up of such patients.

Clinical evaluation of aortic and mitral valve prostheses

The clinical follow-up for a large number of patients with aortic and mitral valve prostheses is now the responsibility of the general internist and cardiologist, particularly those physicians who recommended operation. Proper follow-up of patients with prosthetic heart valves can be performed only if the physician is aware of the "natural history" of the patient following valve replacement as well as of the common complications associated with cardiac valve prostheses. This article discusses the hemodynamic changes which follow cardiac valve replacement, complications associated with valve replacement (congestive heart failure, suture disruption, "ball variance," thromboembolism, hemolysis, cardiomyopathy, etc.) and simple clinical means of detecting these complications. Some special techniques which may be useful in diagnosing complications of prosthetic cardiac valve malfunction are described. It is emphasized that the physician should not consider the patient "cured" once he has undergone cardiac valve replacement, but rather should consider him to be the subject of meticulous long-term medical care.

Echocardiographic and phonocardiographic confirmation of suspected caged mitral valve malfunction

Seven patients studied by echocardiography with and without simultaneous phonocardiography for suspected malfunction of a caged mitral valve prosthesis are presented. In case 1, with inaudible prosthetic clicks, thrombosis of the cage and immobility of the ball were suggested by echocardiographic studies and confirmed at surgery. In case 2, simultaneous echocardiographic and phonocardiographic studies demonstrated wide and variable intervals between the aortic second sound the the opening click and also "sticking" of the ball. In case 3 a thrombus prevented full motion of the ball to the apex of the cage, which was seen on the echocardiogram, while in case 4, with a thrombus within the ventricle and prosthesis, the prosthetic opening click was present intermittently and was associated with only subtle echocardiographic changes. In case 5, echocardiographic studies demonstrated abnormal rocking of the cage secondary to severe prosthetic dehiscence. In case 6, dul prosthetic clicks were to be secondary to a low cardiac-output state. In case 7, with multiple valve prostheses, simultaneous echocardiographic and phonocardiographic studies allowed identification of individual valve sounds and abnormal timing of valve opening. Based on these studies, we believe that echocardiography and simultaneous phonocardiography can yield very useful information in the evaluation of patients with suspected malfunction of a caged mitral valve prosthesis.

Echocardiographic evaluation of the stent mounted aortic bioprosthetic valve in the mitral position. In vitro and in vivo studies

Echocardiograms were performed on 20 clinically stable patients following mitral valve replacement with glutaraldehyde-preserved porcine aortic heterografts and three patients with antibiotic sterilized aortic homografts mounted in the mitral position. Such valves were evaluated in a test chamber at varied flow rates resulting in improved understanding of movements seen with the echocardiogram in vivo. The technique for recording the valvular stent and leaflets is described and a method for measuring several parameters is demonstrated. Initial diastolic slope averaged 2.4 +/- 0.5 cm/sec (range 1.9 to 3.3 cm/sec). Left ventricular outflow tract measured from the anterior portion of the stent to the interventricular septum averaged 1.5 +/- 0.5 cm at end-diastole and 1.3 +/- 0.6 cm at end-systole. Leaflet excursion averaged 1.5 +/- 0.3 cm (with a range from 1.0 to 2.1 cm). The ratio of internal to external stent diameters averaged 0.66 +/- 0.05 (with a range from 0.56 to 0.74).

Noninvasive diagnostic evaluation of the normal Beall mitral prosthesis

Phonocardiography and echocardiography were used to examine 20 patients with a normally functioning Beall disc mitral valve prosthesis. Phonocardiographic intervals were: Q-S1 interval 67 +/- 3 msec; A2-OC interval 118 +/- 8 msec. Maximal variation of the Q-S1 interval within one examination was 21 +/- 2 msec, for A2-OC interval it was 31 +/- 5 msec. Echocardiographic disc velocities were: opening velocity 296 +/- 30 mm/sec, closing velocity 414 +/- 44 mm/sec. Maximal variation of the opening velocity was 126 +/- 25 msec; maximal variation of the closing velocity was 334 +/- 57 msec. Abnormal poppet function was suspected in one patient with unusual prolongation and variability of A2-OC interval.

Diagnosis of prosthetic mitral valve malfunction with combined echo-phonocardiography

Fifty-three patients were studied with combined echo-phonocardiography or phonocardiography alone following prosthetic valve replacement. In sixteen of these patients, clinical deterioration developed, and all subsequently underwent cardiac catheterization and/or surgery. Two patients came to autopsy. Included in this group of sixteen patients were five with obstructed prosthesis, six with paravalvular regurgitation, and five with left ventricular dysfunction. Measurements were made of the time interval from the aortic valve closure sound to the peak opening of the mitral prosthesis determined echocardiographically or to the mitral prosthetic opening click (A2-MVO). Echocardiographic studies of left ventricular wall motion were also performed. The A2-MVO interval was significantly shortened (P less than 0.01) with prosthetic valve obstruction (.05 +/- .02 sec) and paravalvular regurgitation (.05 +/- .01 sec) compared with normally functioning prostheses (Starr-Edwards ball valves .10 +/- .02 sec, Lillehei-Kaster tilting disc prostheses .09 +/- .01 sec). Shortening of this interval was not specific for these conditions because it was sometimes shortened with left ventricular dysfunction. Echocardiographic studies of left ventricular wall motion were helpful in distinguishing among prosthetic valve obstruction, paravalvular regurgitation and left ventricular dysfunction. The combined echo-phonocardiographic technique was especially helpful in detecting malfunction of tilting disc prostheses, because the technique enables measurement of the A2-MVO interval in the absence of an audible opening click.

Spontaneous closure of paravalvular leak after mitral valve replacement

Complications after prosthetic valve replacement may be multiple. In biologic valves, valve detachment and cusp perforation may occur. If this is of significant magnitude, reoperation may be required. This report describes recurrent mitral regurgitation after mitral valve replacement with a Hancock porcine xenograft. The regurgitation subsided spontaneously three months later. We felt that a paravalvular leak closed, with progressive fibrosis and tightening of the annulus. Functional results in this patient were excellent.

Diagnosis and management of complications of prosthetic heart valves

Complications after heart valve replacement remain a substantial source of morbidity and mortality despite continuing advances in surgical care and prosthetic design. Infectious endocarditis occurs in about 4 percent of patients and may appear early (within 60 days) or late after operation. Endocarditis of early onset is commonly due to staphylococcal, fungal or gram-negative organisms and is fatal in 70 percent or more of cases. Infection of late onset is more often of streptococcal origin and the mortality rate is lower, about 35 percent. With either type, prompt recognition, vigorous and appropriate antimicrobial therapy and early consideration of surgical intervention are crucial. The postperfusion and postpericardiotomy syndromes are relatively common and relatively benign syndromes associated with postoperative fever. Their recognition is important to prevent confusion with endocarditis or sepsis and thus to reassure the patient and physician. Treatment is primarily symptomatic. Intravascular hemolysis occurs with most prosthetic heart valves but is more common with certain prostheses and with paraprosthetic valve regurgitation, with significant hemolytic anemia in 5 to 15 percent. Oral iron replacement therapy is effective in the majority of patients, but occasionally blood transfusion or reoperation for leak around the prosthesis is necessary. Prosthesis dysfunction due to thrombus may be recognized clinically by recurrence of heart failure, syncope, cardiomegaly and altered prosthetic valve sounds or new murmurs. Hemodynamic studies verify the diagnosis, and prompt reoperation is indicated for this potentially lethal problem. Systemic embolization has decreased markedly with the introduction of cloth-covered prostheses and is frequently related to erratic or ineffective anticoagulant therapy. We continue to recommend anticoagulant therapy for all patients with prosthetic heart valves unless there is a major contraindication.

Echocardiography in valvular heart disease

Echocardiography is a useful new technique that allows for the diagnosis and assessment of the severity of various forms of valvular heart disease. It is a safe and noninvasive procedure that can readily be used on the critically ill as well as the ambulatory patient. Since the examination can be easily repeated, echocardiography can be used to study a patient over an extended period of time to follow the severity of the disease. With proper care and experience in the performance and interpretation, the cardiologist can derive much useful information to aid in the initial evaluation and long-term follow-up of patients with various forms of valvular disease. With improvements in instrumentation and the use of newer techniques, the usefulness of ultrasound will be further enhanced.