Doppler echocardiographic evaluation of normal and thrombosed Björk-Shiley mitral prosthetic valves

Thrombolytic therapy with recombinant streptokinase for prosthetic valve thrombosis

BACKGROUND

Thrombosis is a serious complication of prosthetic heart valves, and management is often difficult. Thrombolytic therapy is a promising alternative to valve re-operation in the prosthetic valve thrombosis.

METHODS

Fifteen consecutive patients with prosthetic heart valve thrombosis (10 mitral, 3 aortic, 2 tricuspid) were treated with intravenous recombinant streptokinase: 250,000 UI given over 30 minutes followed by an infusion an 100,000 UI per hour, always with clinical monitoring and echocardiographic examinations repeated at 24, 48, and 72 hours after starting thrombolytic therapy. Doppler echocardiography was the primary method use for diagnosis and was also used to follow the response to therapy

RESULTS

Fibrinolytic treatment was successful in 14 (93.3%) patients. Total response was achieved in 13 (86.6%)patients and partial response in 1 (6.7%) patient; one patient died of ventricular fibrillation. No major hemorrhagic events were observed, peripheral embolism occurred in two cases, and one case of minor peripheral bleeding occurred in another. Some patients experienced fever and chills.

CONCLUSIONS

The present study demonstrates the feasibility, safety and efficacy of thrombolytic therapy, which may be considered as first-line therapy for prosthetic heart valve thrombosis.

Thrombolytic therapy for prosthetic valve thrombosis: short- and long-term results

BACKGROUND

Thrombolytic therapy (TT) has evolved as an alternative to surgery for prosthetic valve thrombosis (PVT), but its utility in patient management is still debated and the long-term results are not available.

METHODS

From 1990 through 1999, we treated 110 consecutive patients (52 men, mean age 35.4 +/- 10.8 years) of left-sided obstructive PVT (96 mitral, 14 aortic) with TT (streptokinase in 108, urokinase in 2) according to a specified protocol of prolonged infusion. Serial echo Doppler parameters were monitored in all patients to guide the duration of TT and to quantify its efficacy. Ninety of the 102 survivors of the index episode were followed up for a mean period of 31.3 +/- 27.8 months (range 1-112 months).

RESULTS

Complete hemodynamic response (on cinefluoroscopy and echo Doppler criteria) was seen in 90 (81.8%) episodes, partial response in 11 (10%), and failure in 9 (8.2%). The mean duration of TT was 42.8 +/- 20.4 hours. Five of the 7 patients who were initially seen in cardiogenic shock/overt pulmonary edema died during therapy. After these patients were excluded, the rate of complete response did not differ among patients with New York Heart Association class I/II (80%), class III (86.3%), or class IV (81.5%). The response rate also did not vary with the type, position of prosthesis, duration of symptoms, or time lag since surgery. There were 21 (19.1%) embolic episodes during therapy, including 6 strokes. These were significantly more frequent in patients with atrial fibrillation (AF) (odds ratio on multivariate analysis 2.3, 95% confidence interval 1.3-3.9, P =.01). On follow-up, there were 25 recurrences of PVT, of which 20 again received TT with a complete response in 14 (70%). At 5 years the actuarial survival was 85.2% and the event-free survival was 61.5%. The presence of chronic AF was a significant predictor of recurrence of PVT (odds ratio 2.2, 95% confidence interval 1.2-3.9, P =.008).

CONCLUSIONS

TT is effective in the majority of patients with PVT but is associated with a high rate of embolism, especially in patients with AF. Excluding patients with cardiogenic shock/overt pulmonary edema (in whom TT is largely ineffective), the success of TT does not vary with the New York Heart Association class, duration of symptoms, or other patient variables. The recurrence rates of PVT are high after even successful TT, especially in patients with AF.

Thrombolytic therapy for prosthetic valve thrombosis: a study based on serial Doppler echocardiographic evaluation

Sixteen patients with echocardiographic and cinefluoroscopic evidence of Björk-Shiley prosthetic valve obstruction (13 mitral valves and 3 aortic valves) were treated with intravenous streptokinase. Streptokinase was administered as an initial bolus of 250,000 units for 30 minutes, followed by an infusion of 100,000 units/hr. Serial cinefluoroscopy and echocardiography (M-mode, two-dimensional, and Doppler) were performed at 0, 24, 48, and 72 hours of treatment. The end point of treatment was defined as near normalization of clinical, echocardiographic, and fluoroscopic parameters. Successful thrombolysis was achieved in all patients. The average duration of streptokinase therapy was 43 hours (range 2 to 72 hours). Two of 16 patients had minor systemic embolism during therapy. Short-term follow-up has shown sustained benefit in 14 of 16 patients. Two patients have had rethrombosis of the mitral prosthetic valves and have undergone thrombectomy. Our study demonstrates the feasibility, safety, and efficacy of thrombolytic therapy in the treatment of prosthetic valve thrombosis. It also emphasizes the role of serial Doppler echocardiography in guiding the duration of therapy and assessing its efficacy.

Comparative Doppler evaluation of the monostrut and older convexo-concave Björk-Shiley mitral prosthetic valve

Doppler echocardiography was performed in 104 patients with a Björk-Shiley prosthetic valve in the mitral position. Valves of size 25 mm and 27 mm were inserted in 39 and 65 patients, respectively. Each valve had two models; the older convexo-concave model (22 and 40, of 25 and 27 mm size, respectively). Inflow velocities were recorded using Doppler techniques and the gradients calculated using the Bernoulli principle. The area of the mitral valve was determined by the T1/2 method. Comparison of the two models for both sizes did not reveal any significant differences in either the gradients across the valves or the area of the valve. Trivial mitral regurgitation was detected in a higher percentage of monostrut valves (18% and 20% for the 25 and 27 mm older convexo-concave models and 59.9% and 52% for the 25 and 27 mm monostrut valve). We conclude that the newer monostrut model of the Björk-Shiley valve in the mitral position does not offer any additional haemodynamic benefit.