Medical problems in mitral and multiple valve replacement

Calcific valvular aortic stenosis with and without mitral anular calcium

Seventy-six consecutive patients, mean age 66 +/- 9 years (+/- standard deviation), with isolated aortic valve replacement for calcific valvular aortic stenosis (AS) were studied. Mitral anular calcium (MAC) was detected by echocardiography in 45 patients (59%). Patients with MAC were older (p less than 0.01), had greater peak systolic aortic valve gradients (p less than 0.025), lower cardiac indexes (p less than 0.025) and smaller valve areas (p less than 0.05) than patients without MAC. Thirty-three percent of patients (15 of 45) with MAC required permanent pacemaker implantation after aortic valve replacement, compared with only 10% of patients (3 of 31) without MAC (p less than 0.025). During the follow-up of 7 years (mean 3.8 +/- 1.6), 27% of patients (12 of 45) with MAC died from cardiac causes, compared to only 7% (2 of 31) without MAC (p less than 0.025). Thus, patients with AS and MAC are older, have more severe AS, more frequently undergo permanent pacemaker implantation after aortic valve replacement and more frequently die of cardiac causes than patients with AS and no MAC during follow-up.

Etiology and clinical significance of new fascicular conduction defects following coronary bypass surgery

Two hundred consecutive patients undergoing only coronary bypass surgery were studied. Forty-five patients (group A) developed new fascicular conduction blocks and 155 patients (group B) did not. The 45 patients in group A developed the following fascicular conduction blocks: right bundle branch block 47%, right bundle branch block and left anterior hemiblock 8%, right bundle branch block and first-degree atrioventricular block 2%, left anterior hemiblock 11%, left bundle branch block 18%, right bundle branch block-left anterior hemiblock and first-degree atrioventricular block 5%. There were no significant differences in sex, incidence of diabetes, number of grafts performed, ejection fraction (less than 55%), and perioperative infarction. Group A patients were older (p less than 0.01). Hypertension was found frequently in group A (27 vs 45 patients; p less than 0.01) and was present for a mean of 12.4 years in group A and 4.9 years in group B (p less than 0.01). Preoperative use of digitalis was found in 14 (31%) patients in group A and in 18 (12%) patients in group B (p less than 0.01). Twenty-one (47%) patients in group A had significant disease (greater than 70%) of the left main coronary artery as compared to 17 (10.9%) in group B (p less than 0.001). There was no difference in the recurrence of angina or the survival rate at 14 months. In conclusion, the incidence of new fascicular conduction block after bypass surgery is 22.5%. Long-standing hypertension, left main coronary disease, and the preoperative use of digitalis appear to be predisposing factors. New fascicular conduction block does not affect prognosis.

Aortic valve replacement in childhood: evaluation of left ventricular function by electrocardiography, echocardiography and graded exercise testing

Preoperative and postoperative left ventricular (LV) performance was evaluated noninvasively in 15 children who survived aortic valve replacement (AVR). The noninvasive evaluation included electrocardiography, M-mode echocardiography, and graded exercise testing. Clinically, there was dramatic improvement postoperatively: All but 2 patients were asymptomatic. No conduction defects or arrhythmias were detected preoperatively; however, in the late postoperative period there was a variety of intraventricular conduction abnormalities, myocardial infarctions, and ventricular or supraventricular arrhythmias. On M-mode echocardiography, children with aortic stenosis continued to have increased LV mass postoperatively. Shortening fraction and left-sided systolic time intervals returned to normal. The children with aortic regurgitation also had persistently abnormal LV mass on echocardiography postoperatively. Exercise data indicated no improvement in working capacity after AVR. Also, 9 children (63%) continued to have ST-segment depression with maximal exercise. These data indicate that AVR does not result in a return to normal of myocardial performance in children with severe aortic valve disease.

Systolic and diastolic properties of the human left ventricle during valve replacement for chronic mitral regurgitation

M mode and two dimensional echocardiography were combined with pressure-flow data to analyze systolic mechanics and diastolic compliance in nine patients during valve replacement for chronic mitral regurgitation. Both M mode (six patients) and two dimensional (four patients) echographic analyses revealed large decreases in early postoperative shortening fraction (-24 +/- 17 [standard deviation] percent M mode study, p < 0.01: -30 +/- 12 percent two dimensional study, p < 0.02), which were significantly different from small changes observed in control subjects (M mode study, +7 +/- 10 percent, 25 subjects and two dimensional study, -7 +/- 14 percent, 8 subjects). Additional data suggest that ventricular compliance is increased in chronic mitral regurgitation and that elimination of the low impedance left atrial pathway by valve replacement is associated with a significant increase in wall stress (five patients, p < 0.02) that appears to be responsible for the decreased ejection fraction postoperatively. Analysis of hemodynamic variables other than ejection fraction and rate of circumferential shortening revealed no difference between five postoperative patients with chronic mitral regurgitation and five with coronary artery disease. These results in human subjects confirm predictions from studies in animal models and suggest that unique properties of chronic mitral regurgitation and demand special attention when patients with this condition are being evaluated for surgery.

Left ventricular function in severe pure mitral stenosis as seen at the Kenyatta National Hospital

Twenty-one consecutive Black African patients with severe pure mitral stenosis were evaluated hemodynamically. It was found that advanced mitral stenosis presents itself in Kenya at a very young age (22.9 +/- 9.6 years, mean +/- S.D.), with all but three patients under thirty. Left ventricular angiography demonstrated significant impairment of left ventricular function with 50% of patients having abnormally low valves (mean ejection fraction 0.50 +/- 0.11). This diminished ejection fraction was related primarily to diffuse hypokinesia and an increased endsystolic volume. There was a significant deterioration of ejection fraction with increasing age which could not be correlated to increased severity of mitral stenosis or pulmonary hypertension. It is proposed that the diffuseness of the myocardial involvement and its progression with age in a young population without coronary artery disease represents the resolution of the acute inflammatory process of rheumatic fever in diffuse fibrosis of the myocardium and/or an occlusive vasculitis.

Central haemodynamics at rest and during exercise before and after combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis

Pre- and postoperative haemodynamics were compared in 36 patients with combined aortic and mitral valvular disease. These patients suffered from markedly restricted cardiac function in terms of cardiomegaly, low physical working capacity, hypokinetic central circulation and pulmonary hypertension. Valve replacement was performed with the Björk-Shiley Delrin disc (10) and pyrolytic carbon disc (26) prostheses and followed by subjective improvement in the majority of patients. Heart volume decreased and working capacity increased in average significantly, but were not restored to normal. The main response to surgery was a shift towards a normokinetic circulation, although many patients remained hypokinetic. There was also regression of pulmonary hypertension as a result of reduced left atrial pressure and pulmonary vascular resistance. In spite of a significant decrease in left atrial mean pressure, it remained elevated with prominent v-waves in many patients, particularly during exercise. Marked v-waves in the right atrial pressure curves were also noted in one third of the patients. Only one patient, however, suffered from clinically manifested tricuspid incompetence. This study shows the benefits of combined aortic and mitral valve replacement, even in patients with longterm haemodynamic burden on the myocardium. Although the central haemodynamics were almost normalized at rest, abnormal responses persisted during exercise.

Management of the patient with a prosthetic heart valve

Approximately 20,000 heart valve prostheses are inserted yearly in the United States. Even after successful heart operations, the patients who receive them cannot be regarded as healthy individuals but are a special group with special problems who need close medical attention for the rest of their lives. They are susceptible to many unusual complications because of their implanted foreign body, and it is a challenge to all physicians in contact with them to be aware of their peculiar problems in order to prevent complications if possible and to treat them immediately if they occur. General therapy, surgical complications, infection, and mechanical problems are reviewed, with means for management outlined. These difficulties can be dealt with only by careful follow-up and well-coordinated teamwork between the family physician and the institution where the operation was performed.

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.

Changes in the QRS complex after aortic valve replacement

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Chronic intravascular hemolysis after aortic valve replacement. Long-term study comparing different types of ball-valve prostheses

To assess the severity of hemolysis and to determine whether severity of hemolysis was related to type of prosthesis, hematocrit readings (Hct), schistocyte counts (S), reticulocyte counts (R), and determinations of haptoglobin (Hp), lactic acid dehydrogenase (LDH), bilirubin, urinary hemoglobin, and urinary hemosiderin (Hs) were performed on 54 patients who had three different types of aortic ball-valve prostheses. Hemolysis, as determined by absence of haptoglobins or hemosiderinuria or R>3.5% in the absence of bleeding, was detected in 39 of the 54 patients (72%). S, R, LDH, and bilirubin were higher in patients without haptoglobins than in those with haptoglobins ( P < 0.005). Hematocrits of less than 32% were found in 13 of the 34 patients (38%) with Starr-Edwards valves compared to none of the 11 with Magovern valves ( P < 0.001) and one of the nine with Cutter ( P < 0.05) valves. The combination of S>10 per 1,000 cells, R>5%, and LDH>500 mU was observed only with Starr-Edwards valves (16 of the 34 patients) and was not seen in patients with Magovern or Cutter valves ( P < 0.005). All patients with S>10, R>5%, and LDH>500 mU had hemosiderinuria, and five had hemoglobinuria. Hemoglobinuria was always indicative of severe hemolysis. Hemosiderinuria was rarely detected less than 3 months after operation but was found in 32 of 47 patients so tested (68%) more than 3 months after operation. Hemosiderinuria was found in 25 of 30 patients with Starr-Edwards valves compared to two of the 11 with Magovern valves ( P < 0.001). Hemosiderinuria was also detected in five of six patients with Cutter valves tested, but in three of these the test was only faintly positive. It is concluded that hemolysis is more severe in the presence of Starr-Edwards valves than Magovern or Cutter valves. Based on these observations, the following criteria for rapid clinical evaluation of cardiac hemolysis are suggested: Mild: Hs or absence of Hp but S<10, R<5, LDH<500; moderate: Hs or absence of Hp but S>10, R>5, LDH>500; severe: all of above plus hemoglobinuria.

Experimental mitral valve replacement with a heterograft aortic valve in a rigid metal ring

A mitral valve replacement is described in which a heterograft (pig) aortic valve is supported in a rigid metal ring having three spurs to support the commissures. The ring frame is completely covered by the heterograft, and no artificial material is in contact with the blood stream. Completely fabricated and tested for competency beforehand, it requires only one row of interrupted sutures—after the manner of the Starr-Edwards prosthesis—for insertion, and can be used in either the mitral or the aortic position. Experimental results in the dog indicate that the valve may require only temporary anticoagulation to cover the immediate post-operative period.

Mechanism of thrombus formation upon Starr-Edwards prosthetic mitral valves

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Carcinoid heart disease. Successful repair of the valvular lesions under cardiopulmonary bypass

A patient with carcinoid syndrome with both tricuspid and pulmonic valvular lesions has been described. Successful repair of the valvular lesions was performed under cardiopulmonary bypass. The operation consisted of pulmonic valvotomy with the excision of a single pulmonic valve cusp, and replacement of the tricuspid valve by a Starr-Edwards prosthesis. Postoperatively, the patient noted marked improvement in symptomatology, and there was a concomitant improvement in serial hemodynamic studies.

The development of the signs of tricuspid regurgitation and pulmonic stenosis in patients with metastatic carcinoid tumor should alert the physician to the possible presence of carcinoid heart disease. If hemodynamic and angiocardiographic studies confirm the presence of significant valvular lesions, corrective cardiac surgery should be performed in selected patients.

Serial cardiac output and blood volume studies following cardiac valve replacement

The cardiac output and blood volume were measured preoperatively and sequentially during the early postoperative period in 45 patients undergoing cardiac valve replacement. Most patients showed a prompt, highly significant increase in cardiac output. Those with uncorrected valvular disease, even though apparently trivial, had lower cardiac outputs. The blood volume was sharply reduced from the preoperative level in almost every patient. When this was associated with low cardiac output, replacement of the blood volume deficit was usually accompanied by a prompt increase in cardiac output. Failure to respond in this way occurred only in patients with residual valvular lesions or myocardial disease.