Evaluation of prosthetic valve function and associated complications

Causes and treatment strategies of unilateral leaflet escape of bileaflet mechanical prosthetic heart valves after surgery: a case series

BACKGROUND

During the eleven years from 2010 to 2021, preliminary statistics have shown that Fuwai Hospital completed 23,571 mechanical valve replacements for various types of valves, and 1139 mechanical valve replacements were performed in Guangyuan First People's Hospital. Only two patients developed valve leaflet escape, so valve leaflet escape is a rare postoperative complication.

CASE PRESENTATION

In 2010 and 2021, two patients were selected after they had unilateral leaflet escape after having mechanical valve replacements in Fuwai Hospital of Chinese Academy of Medical Sciences and Guangyuan First People's Hospital. Both patients underwent reoperations with the classic operation and the new bileaflet mechanical prosthetic heart valve was sutured. The treatment of detached single lobe and distal vessel was comprehensively determined, and the condition was treated according to the patient's symptoms, CT results, ultrasound results and other test results, as well as whether this detached lobe caused any abnormal hemodynamics of the distal vessel. The patient with mechanical aortic valve escape completed the 10-year follow-up, and patient with mechanical mitral valve escape completed the 3-month follow-up. there was no thrombosis or hematoma at the embolic site; the patient had no lower limb symptoms.

CONCLUSIONS

The reason for the leaflet escape may be related to the valve design and the leaflet material. If the detached leaflets are damaged and if the distal blood vessels are affected, simultaneous surgical treatment is required. Those patients whose vessels were not damaged by the valve lobe should be carefully monitored.

Mechanical valve obstruction: Review of diagnostic and treatment strategies

Prosthetic valve obstruction (PVO) is a rare but feared complication of mechanical valve replacement. Diagnostic evaluation should focus on differentiating prosthetic valve thrombosis (PVT) from pannus formation, as their treatment options differ. History of sub-optimal anti-coagulation and post-op time course to development of PVO are useful clinical characteristics in differentiating thrombus from pannus formation. Treatment of PVT is influenced by the patient’s symptoms, valve location, degree of obstruction and thrombus size and may include thrombolysis or surgical intervention. Alternatively, pannus formation requires surgical intervention. The purpose of this article is to review the pathophysiology, epidemiology, diagnostic approach and treatment options for aortic and mitral valve PVO.

Diagnosis and Treatment of Left-Sided Prosthetic Paravalvular Regurgitation

Paravalvular leak (PVL) is a complication related to the surgical implantation of left-sided prosthetic valves. The prevalence of paravalvular regurgitation ranges between 5 and 20%. Left-sided prosthetic paravalvular regurgitation presents with a wide constellation of signs and symptoms ranging from asymptomatic murmur to heart failure, hemolysis and cardiac cachexia. Echocardiography plays a key role in imaging the PVL and can help in guiding the closure procedure with both transesophageal and intracardiac probes. Transcatheter closure of paravalvular regurgitations is an appealing prospect.

Obstructive bioprosthetic mitral valve thrombus: management options?

Bioprosthetic valve thrombosis is an extremely rare event, therefore, long-term anticoagulation can be avoided. There is limited experience in the diagnosis and treatment of such a situation. We present the case of a patient with a porcine mitral bioprosthesis who presented with acute pulmonary edema, likely secondary to obstructive valve thrombosis. A favorable outcome was observed after conservative anticoagulant treatment.

Prosthetic heart valve obstruction: thrombolysis or surgical treatment?

Prosthetic valve thrombosis is a potentially life-threatening complication associated with high morbidity and mortality. Transthorasic and transoesophageal echocardiography play an important role to the diagnosis and provides incremental information about the optimal treatment strategy, while fluoroscopy and cardiac computed tomography may be of added value. Guidelines differ on whether surgical treatment or fibrinolysis should be the treatment of choice for the management of left-sided prosthetic valve thrombosis and these uncertainties underline the need for further prospective randomized controlled trials. Thrombus size, New York Heart Association functional class of the patient, the possible contraindications, the availability of each therapeutic option and the clinician's experience are important determinants for the management of prosthetic valve thrombosis.

Blockage of a mechanical aortic valve leaflet with Bioglue: a case report

Mechanical aortic valve dysfunction is a very rare event and is usually due to thrombosis, pannus overgrowth, or both. BioGlue as a cause for such a complication has been reported only occasionally. We describe a case of a 63-year-old woman who underwent operation for symptomatic tight aortic stenosis. After implantation of an aortic valve (AGN-751, size 19; St. Jude Medical, St. Paul, MN, USA) because of a transverse tear of the aortic wall above the annulus occurring during the suturing of the aortotomy, a triangular Vascutek Dacron patch (Vascutek/Terumo, Inchinnan, Scotland, UK) was included. To secure hemostasis, BioGlue (CryoLife, Kennesaw, GA, USA) was applied. A transthoracic echocardiography (TTE) examination performed after signs of ischemia appeared in the electrocardiogram on postoperative day 5 revealed an aortic transvalvular gradient of 74/38 mm Hg and a functional valve area of 1.0 cm2. No coronary lesions were revealed in a coronarography evaluation, but cinefluoroscopy (CF) examination revealed immobility of 1 valve leaflet. The reoperation revealed a thick, rough layer of the glue on the inner side of the patch. This glue had run down to the valve, blocking a mechanical leaflet. Cleaning the valve was not possible, and the valve had to be changed. The subsequent postoperative course was uneventful. The transvalvular gradient was 39/20 mm Hg, and the functional valve area was 1.2 cm2. We believe that the use of BioGlue and other surgical sealants is justified to secure complex suture lines and for maintaining hemostasis in cardiac surgery, but some precautionary rules must be respected. Authors have indicated that the glue enters through the needle holes in such cases, but our findings suggest it can also pass to the Dacron patch itself. CF is superior to TTE and transesophageal echocardiography for analyzing movement of the mechanical valve leaflet, and cardiac catheterization is rarely needed.

Trileaflet valve hydrodynamic resistance assessment

Valve hydrodynamic performance is usually assessed by effective orifice area, transvalvular resistance, regurgitation and blood damage effect. Some studies suggest effects in effective orifice area due to cardiovascular resistance, compliance and angle position of the valve. We suppose that silicone rubber valves under study have a good performance under different cardiovascular resistance conditions. Two in vitro experiments were made to test this hypothesis under constant and pulsatile flow rate. Transvalvular gradient pressure, transvalvular resistance, Gorling effective orifice area, effective orifice area in the ascending aorta and Reynolds numbers were estimated in both flow rates. Results suggest that cardiovascular resistance has no significant effect for this kind of valves, however resistance effect is observed in pumping pressure. Small transvalvular resistance and transvalvular pressure gradients were found. Gorlin effective orifice areas greater than 0.3 cm(2) have not viscosity effect. P-value 0.001 was found between Gorlin effective orifice area under constant and pulsatile flow rate.

Changes in aortic root function after valve replacement in patients with aortic stenosis

BACKGROUND

Aortic elastic properties are compromised in various states that induce functional and histological changes in the aortic wall. Aortic stenosis is frequent and often requires replacement of the stenotic valve. The purpose of this study was to examine the effect of aortic valve replacement on the aortic root function.

METHODS

31 patients, mean+/-SD age 67.2+/-9.1 years with severe aortic stenosis, who underwent aortic valve replacement with a bileaflet mechanical prosthesis, were studied. Aortic root function indices such as aortic cross-sectional compliance (CSC), aortic root distensibility (ARD), and aortic stiffness index (ASI) were calculated with the use of M-mode echocardiography in three sessions: one preoperatively (pre-op), one on day 7 postoperatively (early post-op), and one 6 months postoperatively (late post-op).

RESULTS

Aortic root function deteriorated early post-op (p<0.001 for all) and returned towards pre-op levels late post-op (p=NS for all). CSC changed from 2.84+/-1.98 to 1.37+/-0.92, and 2.30+/-1.11 cm2/mmHg, ARD from 2.21+/-5.60 to 1.01+/-0.67, and 1.79+/-0.96 cm2/dyne, and ASI from 9.72+/-5.60 to 24.65+/-19.10, and 11.51+/-7.85, respectively. Correlations were found between early changes in some aortic root indices and the degree of aortic stenosis, denoting that aortic function deteriorated less in more severe cases of aortic stenosis. None of the late changes were related to aortic valve or left ventricular indices.

CONCLUSIONS

Aortic valve replacement with a mechanical valve results in a significant but transient impairment of aortic distensibility.

Prosthetic heart valve thrombosis: pathogenesis, diagnosis and management

Thrombosis of a prosthetic valve is one of the most severe complications of cardiac valve replacement. The incidence is 0.5% in the aortic and mitral positions and up to 20% in the tricuspid position. The presenting clinical picture ranges from the absence of symptoms to cardiogenic shock. The traditional treatment of this complication has been emergency surgery, but thrombolysis, which has been available for many years, is being considered as the first line of treatment more and more every day. The pathogenesis, diagnosis and treatment of thrombosis of prosthetic heart valves are reviewed here. Thrombolysis, which has an efficacy of over 80%, is emphasized in this review. Embolic complications associated with this therapeutic approach remain a great concern with rates of 3% to 10%, and some authors reporting rates up to 20%.

In vivo short-term doppler hemodynamic profiles of 189 carpentier-edwards perimount pericardial bioprosthetic valves in the mitral position

We sought to determine the hemodynamic performance of the Carpentier-Edwards Perimount pericardial valve in the mitral position. We reviewed the Doppler echocardiographic data on 189 patients (110 women; 68 +/- 12 years of age) who were implanted with this valve (7.6 days +/- 13 postoperatively) at our institution between September 2000 and May 2002. The average ejection fraction was 47%. For all valves, the peak velocity was 1.9 +/- 0.3 m/s, peak gradient was 15 +/- 4.8 mm Hg, and mean gradient was 5.8 +/- 2 mm Hg. The pressure half-time was 93 +/- 24 milliseconds, with a calculated effective orifice area of 2.5 +/- 0.6 cm2. The average effective orifice area by continuity equation (83 valves) was 1.5 +/- 0.5 cm2. The mitral regurgitation was graded mild or less in 97.5% of all valves. This is the largest series establishing the favorable hemodynamic behavior of the different sizes of a new Perimount mitral valve, and the reported data could serve as a reference.

Successful thrombolysis of a partially obstructed bileaflet prosthetic heart valve in the mitral position

We describe the case of a woman who presented with dyspnea of abrupt onset and who had recently undergone replacement of the mitral valve with a bileaflet mechanical prosthesis. Transthoracic echocardiographic examination with spectral Doppler recording of transvalvular blood flow revealed a velocity spectrum consistent with obstruction. Transesophageal echocardiography demonstrated partial obstruction of the prosthetic valve due to immobilization of 1 hemidisc in the closed position. This immobilization was apparently caused by a small mass whose appearance was consistent with that of a thrombus. The patient was successfully treated by intravenous administration of a thrombolytic agent. This case demonstrates the value of transesophageal echocardiography in the selection of candidates for thrombolytic treatment in cases of thrombosis of a left-sided valve prosthesis.

When and how does nonstructural mechanical prosthetic heart valve dysfunction occur?

OBJECTIVE

We discuss the clinical aspects related to mechanical valve dysfunction based upon 20 years' experience of our cases.

METHODS

Between January 1982 and December 2001, 21 patients underwent surgical interventions because of mechanical valve dysfunction. Thirteen men and 8 women (mean age 47 +/- 20, range 3-75 years-old), were included.

RESULTS

Mitral valve dysfunction was observed in 12 patients. Prosthetic valve stenosis occurred in 6 patients between 2 and 224 months, and paravalvular leaks in 4 between 1 and 71 months after surgery. The other 2 patients suffered from hemolytic anemia with mild paravalvular leaks between 102 and 104 months after surgery. Aortic valve dysfunction was observed in 8 patients including 3 stenotic lesions between 48 and 97 months and 5 paravalvular leaks between 3 and 150 months after surgery. Tricuspid regurgitation was seen in 1 patient with a huge right atrium at 42 months after surgery. Early death was seen in 1 patient. Late death occurred in 1 patient, 17 years after operation. Survival, including early death, was 95.2%, at 10 and 15 years. One valve-related complication of bioprosthetic valve endocarditis at the mitral and tricuspid positions occurred 12 years after a reoperation. The freedom from complications was 95.2% at 10 years, and 76.2% at 15 years.

CONCLUSIONS

Paravalvular leaks without overt endocarditis had latency periods of up to 12 years, and pannus formation was observed 20 years after surgery. Early and late clinical results after surgery for mechanical valve dysfunction were excellent.

Prosthetic valve malfunction masked by intraoperative pressure measurements

IMPLICATIONS

We describe a case in which intraoperative echocardiography recorded an abnormally high pressure gradient across a newly implanted mechanical heart valve. However, inserting pressure-transducing needles on each side of this prosthesis did not confirm the echocardiographic findings. The prosthesis was later confirmed to be malfunctioning and was replaced.

Peak early diastolic velocity rather than pressure half-time is the best index of mechanical prosthetic mitral valve function

Reliable screening of mechanical prosthetic mitral valve (PMV) dysfunction by transthoracic echocardiography (TTE) is mandatory because transesophageal echocardiography (TEE) cannot be routinely used. However, acoustic shadowing seriously hampers detection of PMV dysfunction with TTE, particularly regurgitation. To identify TTE indexes that can detect PMV dysfunction (regurgitation or obstruction), 134 patients (age 60 +/- 12 years, 64 men) with PMV who underwent TTE and TEE within 3 +/- 5 days were assessed. There were 73 normal and 61 dysfunctional valves (40 regurgitant, 21 obstructive). By multivariate analysis, peak E velocity was the best predictor of a dysfunctional valve. Both peak E velocity (E > or =1.9 m/s; sensitivity 92%, specificity 78%) and the ratio of velocity-time integrals of flow through the prosthesis to that of the left ventricular outflow (VTI(pmv/)VTI(lvo) > or =2.2; sensitivity 91%, specificity 74%) were successful in detecting PMV dysfunction. Although pressure half-time (PHT) readily identified PMV obstruction, it did not detect regurgitation. Logistic models including peak E velocity and VTI(pmv)/VTI(lvo) or PHT were equally successful in detecting PMV dysfunction. However, all 3 variables were needed to best distinguish among normal, obstructed, and regurgitant valves. A peak E velocity > or =1.9 m/s and VTI(pmv)/VTI(lvo) ratio > or =2.2 predicted valve regurgitation in 83% of valves when PHT was < 130 ms, and valve stenosis in 95% when PHT was >130 ms. Importantly, a peak E velocity < 1.9 m/s, VTI(pmv)/VTI(lvo) ratio < 2.2, and a PHT < 130 ms had a predictive accuracy for a normal valve of 98%. Thus, TTE Doppler indexes can be used as screening parameters of PMV dysfunction and help select patients for further diagnostic evaluation with TEE.