First I would like to note that the management decision is highly controversial. We have managed patients with thrombosed mechanical valves both surgically and with thrombolysis depending on physician preference and patient wishes or condition. Embolic and fatal bleeding complications have been seen with thrombolysis as well as mortality with surgery.
Discussion: Obstructive thrombosed prosthetic heart valve (OTPHV) is a rare but serious complication that we sometimes face. Obstruction of prosthetic heart valves may be caused by thrombus formation, pannus ingrowth, or a combination of both. The cause may be difficult to determine and requires knowledge of the clinical presentation and findings on echocardiography, including transesophageal echocardiography.
There are 2 forms of therapy, thrombolytic therapy and surgical replacement of the OTPHV. The 2006 American College of Cardiology/American Heart Association guidelines provide Class II recommendations in which the level of evidence was “C” in all 3 of the IIa recommendations and in 2 of the 4 IIb recommendations.The general principles were that thrombolysis may not be successful and carries a higher risk of embolization or bleeding. The European guidelines published in 2012 favor surgery except in conditions where it is not readily available or the patient is considered high risk.
A recent authoritative review on this issue that is recommended to be read (reference 1) included a literature search from 1995 to 2012. The search eventually yielded 17 studies, comprising 756 patients which were related to thrombolytic agents in OTPHV and 13 studies, comprising 662 patients which were related to surgery in OTPHV.
Of the data that were available in 665 patients with thrombolysis, the majority of the patients were female (59%); 35% presented in NYHA class 1 and 2 and 65% in class 3 or 4. Complete success was achieved in 81% of patients presenting in NYHA functional classes I/II and 74% of patients presenting in NYHA functional classes III/IV. Streptokinase was used in 12 of the 17 studies. The rate of cerebrovascular accident (CVA) or embolic phenomenon to other arterial sites was 14%. Some studies included tricuspid OTPHV; excluding these, 481 involved the mitral PHV, and 151 involved the aortic PHV.
Thirteen studies presented baseline patient characteristics and clinical outcomes in 662 patients with OTPHV who were treated surgically. In 10 studies of 543 patients, 490 (91%) had surgery as the initial therapy of OTPHV. In other words, in these 10 studies, 9% of the patients had surgery following failure of thrombolytic therapy. All patients had received a mechanical PHV. Eighty-one percent of patients with OTPHV were in NYHA functional classes III/IV. Occurrence of CVA or emboli was 6%. 21 patients had a recurrence of OTPHV. The 30-day mortality was 15% which may be partly related to a high incidence (81%) of NYHA functional classes III/IV at clinical presentation.
Conclusions of the review and recommendations:
1. Tricuspid OTPHV:
Thrombolytic therapy was successful in 88% of the patients; surgery can be reserved for those in whom thrombolysis is not adequate
2. Left-sided OTPHV (mitral, aortic): Thrombolysis is first choice when:
Surgery is not a viable option or if patient refuses surgery.
Patients in NYHA functional class I/II.
Those with very severe comorbid conditions that would be associated with a very high surgical operative mortality.
“Small thrombus” (area <0.8 cm2) with or without previous stroke.
3. Surgery may be the preferred therapy initially for:
Patients in NYHA functional class III/IV
Large thrombus burden (area _0.8 cm2)
Pannus is a significant contributor to the obstruction or a suspected long duration of the obstruction.
Prosthesis replacement that is necessary or appropriate
Contraindications to thrombolytic therapy
Surgery that may be needed urgently in those with unsuccessful thrombolysis.
* Treatment of Obstructive thrombosed Heart valves. Grace Huang, MD, Hartzell V. Schaff, MD, Thoralf M. Sundt, MD, Shahbudin H. Rahimtoola, MB, FRCP, DSC (HON)
Journal of the American College of Cardiology, 2013:Volume 62, page 1731