Perspective:

The following are 10 points to remember about this review article:

1. Paravalvular leaks (PVLs) occur relatively commonly in patients who have undergone surgical valve replacement, with an incidence of 2-10% in the aortic position and 7-17% in the mitral position. Most PVLs are asymptomatic, but serious clinical sequelae are seen in 1-5% of the cases.

2. The risk factors for PVL include annular calcification, infection, suturing technique, as well as the size and shape of prosthetic implant. Early PVLs are usually associated with a technical issue in relation to the surgery, whereas late PVLs are often a consequence of suture dehiscence caused by endocarditis or the gradual resorption of incompletely debrided annular calcifications.

3. The commonest symptom in patients with symptomatic PVLs is congestive heart failure from volume overload, which develops in ~90% of cases, whereas hemolytic anemia is seen in one-third to three-quarters of cases.

4. Intravascular hemolysis from PVL can be identified by a serum lactate dehydrogenase level >460 U/L and any two of the four following criteria: blood hemoglobin, <13.8 g/dl for males or <12.4 g/dl for females, serum haptoglobin <50 mg/dl, and reticulocyte count >2%. Plasma-free hemoglobin levels >40 mg/dl are also suggestive of hemolysis.

5. Echocardiography and computed tomography (CT) are the preferred imaging technologies for evaluation of PVLs, as well as to guide closure of PVLs. Pre-acquired 4D-CT angiography (CTA) reconstructed images can be displayed in many catheterization laboratories either adjacent to or overlaid onto live fluoroscopy, a technique referred to as fusion imaging.

6. Medical therapy is palliative and usually ineffective. Patients with hemolysis may require iron and folate supplementation and use of erythropoietin. Blood transfusions are often necessary, but sensitization eventually develops and definitive therapy, if feasible, should be considered early.

7. Surgery has been traditionally considered the definitive therapy for symptomatic PVLs, and usually involves either repair of the leak or re-replacement of the valve. Leak repairs usually involve direct suturing, patch closure, and incorporation of full-thickness autologous tissue. Failure rate of surgery ranges from 12% to 35%.

8. Transcatheter closure of PVLs has emerged as a viable option, with high success rates in experienced centers. PVL closure requires a multi-disciplinary approach with close collaboration between interventional cardiologists, echocardiographers, CTA reconstruction specialists, cardiovascular surgeons, and anesthesiologists.

9. The transcatheter closure of PVLs is performed using transseptal, retrograde transaortic, and/or left ventricular transapical approaches. The choice of approach depends on the valve involved, the location of the leak, and the type and location of mechanical valves hindering entry.

10. The results of transcatheter PVL closure have been generally favorable, with major complications occurring in approximately 8% of patients. Emergent cardiac surgery is required in 0.7-2%, and death has occurred in 1.4-2%. Transapical access is associated with hemothorax in 2.5-2.8%, while there have been rare cases of coronary artery damage, acute myocardial infarction, cardiac tamponade, and pneumothorax. Device embolization has been reported in 0.7-4%, and device interference with the prosthetic valve occurs in 3.5-5%. The long-term outcome of patients with transcatheter closure of PVL is similar to that of patients treated surgically.