The Left Atrial V-Wave After Mitral Valve Replacement

Clinical course and hemodynamic observations after supraannular mitral valve replacement in infants and children

OBJECTIVES

We report the clinical course and unique hemodynamic findings after placement of a supraannular mitral valve prosthesis.

BACKGROUND

Children with symptomatic mitral valve disease whose annulus is too small for the smallest prosthesis are difficult to manage. One option is valve replacement with a prosthesis positioned entirely within the left atrium (LA).

METHODS

We reviewed 17 patients (median age 10 months) with symptomatic mitral valve disease who underwent placement of a supraannular valve prosthesis between 1980 and 1994.

RESULTS

The actuarial survival rates were 88% at 1 month and 71%, 62% and 53% at 1, 2 and 10 years, respectively. Preoperative hemodynamic data (mean +/- SD)) compared with those after placement of the supraannular mitral prosthesis were as follows: "a" wave to left ventricular end-diastolic pressure gradient 17 +/- 5 versus 4 +/- 4 mm Hg (p = 0.003), mean LA pressure 25 +/- 6 versus 20 +/- 6 mm Hg (p = 0.07), "a" wave 30 +/- 6 versus 19 +/- 5 mm Hg (p = 0.006), "v" wave 28 +/- 5 versus 30 +/- 9 mm Hg (p = 0.31), mean pulmonary artery pressure 54 +/- 19 versus 42 +/- 15 mm Hg (p = 0.07) and left ventricular end-diastolic pressure 14 +/- 5 versus 16 +/- 4 mm Hg (p = 0.12).

CONCLUSIONS

Supraannular mitral valve replacement provides relief of mitral stenosis or mitral regurgitation. However, LA to left ventricular early diastolic gradients with large atrial "v" waves contribute to elevated mean LA pressures in the absence of prosthetic valve obstruction or regurgitation. As a result of this unexpected finding, associated left heart obstructive lesions and pulmonary and left ventricular end-diastolic hypertension, the outlook remains poor.

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.

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.

Clinical and haemodynamic observations after combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis. Early and late results in 25 patients

Combined mitral and aortic valve replacement with the Björk-Shiley tilting disc valve (pyrolite) was performed in 25 unselected patients characterized by markedly impaired functional capacity, hypokinetic central circulation and cardiomegaly before operation. Surgery was performed during extracorporeal circulation with deep hypothermia. The mitral valve was replaced first in all cases. There were no intra-operative deaths, but 2 patients died while still in hospital (8.0%). One patient died 2 months postoperatively due to progressive heart failure. The remaining patients--with the exception of one who had died of cancer of the ovary--were re-examined in average 28.7 (18-40) months postoperatively. Most patients had improved symptomatically and were in functional classes I-II (N.Y.H.A.). The haemodynamic findings indicated restoration to normal resting values of cardiac output, pulmonary artery pressure and pulmonary vascular resistance, but with an increase in left ventricular end-diastolic pressure (LVEDP). The mean diastolic gradient across the mitral prosthesis varied from 0 to 11 mmHg, while simultaneous pressure recordings from the left ventricle and the aorta, with one exception, disclosed no systolic pressure gradients (peak) across the aortic valve. Postoperative arterial thrombo-embolic complications occurred in 2 patients, resulting in only minor neurological sequelae.

Pulmonary vein flow pattern in mitral incompetence, combined mitral stenosis/incompetence and after prosthetic valve replacement

Pulmonary vein flow (PVF) pattern was studied with an electromagnetic flowmeter in 11 patients with combined mitral stenosis/incompetence (MS/MI), in 6 patients with pure mitral incompetence (MI) and in 24 patients after mitral valve replacement (MVR). ECG, left atrial and left ventricular pressures were recorded simultaneously. The anomalous flow patterns, which were recorded, reflected the left atrial events and mitral valve function. Before MVR, the major forward flow occurred in ventricular diastole. In patients with predominating MS and small/moderate MI, a small retrograde PVF (RF) occurred in early ventricular systole, while pure or combined severe MI produced a holosystolic reversal of PVF.