acute prosthetic valve failure

Acute Prosthetic valve failure

By Prof. Dr. Mohammed UsamaNHI

Case report• 44 yo male• Presented with NSTEMI• Hx of AoVR 3 years earlier by single leaflet tilting

disc No. 21 valve• Presented with an episode of chest pain that was

relieved on admission, then recurred 2 hours later• ECG did not show any new changes, but the

patient was in cardiogenic shock• Transthoracic echo normally functioning valve,

normal LV function• The episode was relieved spontaniously but

recurred with ST depression

• Coronary angio and fluoroscopy revealed normal coronaries and a well functioning prosthetic valve

• A third episode of cardiogenic shock occurred, TTE showed massive Ao regurge

• the patient recovered spontaneously and was urgently transmitted to the operating theatre where he had a prosthetic aortic valve replacement with a No. 21 Edwards Mira Ultra Finesse mechanical valve.

• Abnormal pannus proliferation trapping the right ventricular side orifice of the mechanical aortic valve and causing intermittent acute aortic regurgitation was found. After the operation the patient had an uncomplicated recovery and was discharged on his 7th postoperative day.

Types of prosthetic valves• Mechanical valves are those that are manufactured

entirely from manmade materials; these valves typically have a tilting disk or bileaflet design and are composed of carbon alloys.

• Biological valves are composed primarily of material that originated as living tissue, including porcine aortic valves, valves manufactured from bovine pericardium, valves transplanted from other human beings (homografts), and autografts from the patient.

Complications of prosthetic valves• Structural deterioration, particularly with

bioprosthetic valves• Valve obstruction due to thrombosis or pannus

formation• Systemic embolization• Bleeding• Endocarditis and other infections• Left ventricular systolic dysfunction, which may be

pre-existing• Hemolytic anemia

Mechanical versus bioprosthetic valves

• Overall patient survival was similar — 38 percent for mechanical valves versus 43 percent for bioprostheses

• The likelihood of structural failure with bioprosthetic valves was 15 percent for aortic valves and 36 percent for mitral valves; there were no failures with mechanical valves

• The risk of bleeding was greater with mechanical valves (42 versus 26 percent)

Serial monitoring in patients with prosthetic valves

Spectrum of paravalvular regurgitation

• new, often severe regurgitation results from prosthetic valve endocarditis or structural failure.

• A variety of factors can contribute to structural failure with bioprosthetic valves, including mechanical stress, immunologic rejection, endocarditis, and cusp tear, leading to severe valvular regurgitation.

Acute valve thrombosis

• Prosthetic valve thrombosis (PVT), which can lead to valvular obstruction, occurs with equal frequency in patients with bioprosthetic valves and in those with mechanical valves who are treated with anticoagulants.

• The reported annual incidence of PVT ranges from 0.03 to 5.7 percent; higher rates are observed in patients with mitral prostheses (in some reports) and/or subtherapeutic anticoagulation

Dx of Acute valve thrombosis

• The gold standard for the diagnosis of PVT is transesophageal echocardiography (TEE) and/or cine-fluoroscopy to assess both valve motion and clot burden.

• transthoracic Doppler echocardiography can establish the diagnosis in many patients and is also indicated to assess hemodynamic severity.

Treatment: surgery vs thrombolysis

• With surgery, there is a high operative mortality that is largely related to clinical functional class (17.5 percent in patients in NYHA class IV compared to 4.7 percent with less severe disease).

• With thrombolysis, Complications occurrs in 25 percent of patients. These includs major bleeding in 4.7 percent, systemic embolization in 15 percent, and death in 11.8 percent due to complications or primary failure of therapy.

Thrombolysis: risk stratification

• It may be possible to stratify patients undergoing thrombolysis according to the risk of complications.

• Significant predictors of complications were thrombus area by TEE ≥0.8 cm2 and prior history of stroke. Patients with neither risk factor had a complication rate of 8 percent, while those with both risk factors had a complication rate of 79 percent.

Thrombolysis: risk stratification

• It may be possible to stratify patients undergoing thrombolysis according to the risk of complications.

• Significant predictors of complications were thrombus area by TEE ≥0.8 cm2 and prior history of stroke. Patients with neither risk factor had a complication rate of 8 percent, while those with both risk factors had a complication rate of 79 percent.

Thank You!