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Early Thrombotic Stenosis of Aortic Bioprosthetic Valves: Report of Two Cases

1993; Elsevier BV; Volume: 68; Issue: 7 Linguagem: Inglês

10.1016/s0025-6196(12)60607-7

1942-5546

Farid Gharagozloo, Charles J. Mullany, Thomas A. Orszulak,

Hydrogen embrittlement and corrosion behaviors in metals

Thrombotic stenosis of a Carpentier-Edwards porcine bioprosthesis occurred in two patients within 3 months after aortic valve replacement. Both patients underwent successful replacement of the aortic prosthesis. Although previously reported, this complication of aortic porcine bioprostheses is uncommon. Thrombotic stenosis of a Carpentier-Edwards porcine bioprosthesis occurred in two patients within 3 months after aortic valve replacement. Both patients underwent successful replacement of the aortic prosthesis. Although previously reported, this complication of aortic porcine bioprostheses is uncommon. Thrombotic stenosis of porcine bioprosthetic valves early after cardiac operation is a rare but serious complication that is not well recognized. Herein we describe two cases of early thrombosis of porcine valves in the aortic position 8 and 10 weeks after implantation. A 73-year-old woman came to our institution because of severe aortic regurgitation and triple-vessel coronary artery disease. The ejection fraction was 55%. She underwent quadruple coronary artery bypass grafting and aortic valve replacement; a 23-mm Carpentier-Edwards porcine bioprosthesis was used. Heparin was administered intravenously for 3 days postoperatively; the highest activated partial thromboplastin time was 44.6 seconds. She had an uncomplicated recovery and was dismissed on the eighth postoperative day. She was taking the following medications: aspirin, 81 mg/day; dipyridamole (Persantine), 75 mg three times a day; triamterene with hydrochlorothiazide (Dyazide), once a day; levothyroxine sodium (Synthroid), 0.1 mg/day; and conjugated estrogens (Premarin), 0.625 mg/day. The patient was readmitted 7 weeks later because of chest pain suggestive of angina pectoris. Her temperature was 37°C. The hemoglobin concentration was 11.3 g/dl, the leukocyte count was 7.9 × 103/mm3, and the platelet count was 267 × 103/mm3. Repeated cardiac catheterization revealed patent grafts but a gradient of 30 to 40 mm Hg across the aortic valve. We thought that reoperation might be necessary; however, because the patient's condition improved symptomatically, we decided to reexamine her in 2 to 4 weeks. Three weeks later, an echocardiogram disclosed a mean aortic valve gradient of 62 mm Hg. Reoperation was undertaken. At operation, all three cusps of the porcine bioprosthesis were filled with fibrinous material (Fig. 1). A histologic examination of the bioprosthesis showed extensive thrombus that filled the valve leaflets; two of them were essentially immobile. The valve was excised (it was not cultured) and replaced with a 23-mm Medtronic-Hall prosthesis. The patient's postoperative course was uneventful. A 67-year-old man came to our institution because of severe symptomatic aortic stenosis. His coronary arteries were normal, and the ejection fraction was 30%. A 23-mm Carpentier-Edwards porcine bioprosthesis was inserted, and the patient's postoperative recovery was uneventful. He was dismissed 9 days later in sinus rhythm, and he was taking aspirin (81 mg/day) and digoxin (0.25 mg/day). Initially, the patient was well, but he returned 8 weeks later because of recurrent symptoms of angina pectoris and shortness of breath. His temperature was 36.9°C. The hemoglobin concentration was 12.0 g/dl, the leukocyte count was 7.3 × 103/mm3, and the platelet count was 203 × 103/mm3. An echocardiogram revealed severe stenosis of the aortic prosthesis and a mean pressure gradient of 55 mm Hg. The patient underwent reoperation. The prosthetic aortic valve was well seated. The three leaflets were immobile, and the valve was severely stenotic. The concave surfaces of all three leaflets were filled with pale pink firm material that restricted the movement of the leaflets. A histologic examination disclosed bland thrombus that coated the aortic surface of the leaflets, which were intact. The valve was excised (it was not cultured) and replaced with a 23-mm Medtronic-Hall prosthesis. The patient's recovery was uneventful. Since they were introduced in the late 1960s, glutaraldehyde-preserved porcine valve prostheses have been widely accepted and used. Their widespread application has been due to their central flow characteristics and the low rate of thrombogenicity without the need for long-term anticoagulant therapy. The only perceived disadvantages of these valves have been tissue degeneration and possibly a second valve replacement, especially in young patients or those with renal failure. Thrombosis of porcine bioprostheses early after mitral valve replacement, particularly in patients with chronic atrial fibrillation, an enlarged left atrium, and low cardiac output, has been described.1Thiene G Bortolotti U Panizzon G Milano A Gallucci V Pathologic substrates of thrombus formation after heart valve replacement with the Hancock bioprosthesis.J Thorac Cardiovasc Surg. 1980; 80: 414-423PubMed Google Scholar Early thrombosis of porcine bioprostheses after aortic valve replacement, however, has not been recognized as readily. The reports of thrombosis of porcine bioprostheses in the aortic position are summarized in Table 1.2Cohen DJ Kishel J Likoff M Harken AH Risk of prosthetic thrombosis with a porcine heterograft valve in the aortic position: case reports.Mil Med. 1982; 147: 1056-1058PubMed Google Scholar, 3Fishbein MC Gissen SA Collins Jr, JJ Barsamian EM Cohn LH Pathologic findings after cardiac valve replacement with glutaraldehyde-fixed porcine valves.Am J Cardiol. 1977; 40: 331-337Abstract Full Text PDF PubMed Scopus (114) Google Scholar, 4Croft CH Buja LM Floresca MZ Nicod P Estrera A Late thrombotic obstruction of aortic porcine bioprostheses.Am J Cardiol. 1986; 57: 355-356Abstract Full Text PDF PubMed Scopus (9) Google Scholar, 5Lesnefsky EJ Groves BM Woelfel GF Dauber IM Campbell DN Early thrombosis of a porcine bioprosthesis in the aortic valve position.Am J Cardiol. 1986; 58: 1120-1121Abstract Full Text PDF PubMed Scopus (8) Google Scholar, 6Baciewicz PA del Rio C Goncalves MA Lattouf OM Guyton RA Morris DC Catastrophic thrombosis of porcine aortic bioprostheses.Ann Thorac Surg. 1990; 50: 817-819Abstract Full Text PDF PubMed Scopus (13) Google Scholar, 7Amidi M Ferson PF Labuda MJ Melhem MS Early manifestation of noncalcific aortic stenosis after porcine valve replacement.Ann Thorac Surg. 1990; 49: 471-472Abstract Full Text PDF PubMed Scopus (4) Google Scholar Of the 10 cases, 8 occurred within 6 months after surgical treatment. In one instance, early thrombosis was associated with carcinoma of the prostate, use of estrogen, and a possible hypercoagulable state; however, most patients had no antecedent factors related to thrombotic problems.Table 1Reported Cases of Thrombotic Obstruction of Aortic Porcine BioprosthesesReferenceAge (yr) and sexProsthesis*C-E = Carpentier-Edwards.Occurrence of obstruction after valve replacement (mo)Anticoagulant statusAssociated conditionsReplacement valve and survival statusCohen et al2Cohen DJ Kishel J Likoff M Harken AH Risk of prosthetic thrombosis with a porcine heterograft valve in the aortic position: case reports.Mil Med. 1982; 147: 1056-1058PubMed Google Scholar47 M25-mm C-E3……St. Jude medical; aliveFishbein et al3Fishbein MC Gissen SA Collins Jr, JJ Barsamian EM Cohn LH Pathologic findings after cardiac valve replacement with glutaraldehyde-fixed porcine valves.Am J Cardiol. 1977; 40: 331-337Abstract Full Text PDF PubMed Scopus (114) Google Scholar83 M23-mm Hancock3 1/2…Carcinoma of prostate; estrogen therapyNo surgical intervention; deadCroft et al4Croft CH Buja LM Floresca MZ Nicod P Estrera A Late thrombotic obstruction of aortic porcine bioprostheses.Am J Cardiol. 1986; 57: 355-356Abstract Full Text PDF PubMed Scopus (9) Google Scholar54 M27-mm C-E38Unknown…Medtronic-Hall; alive22 M25-mm Hancock9Unknown…No surgical intervention; deadLesnefsky et al5Lesnefsky EJ Groves BM Woelfel GF Dauber IM Campbell DN Early thrombosis of a porcine bioprosthesis in the aortic valve position.Am J Cardiol. 1986; 58: 1120-1121Abstract Full Text PDF PubMed Scopus (8) Google Scholar60 M23-mm C-E6Sodium warfarin (2 mo)…St. Jude medical; aliveBaciewicz et al6Baciewicz PA del Rio C Goncalves MA Lattouf OM Guyton RA Morris DC Catastrophic thrombosis of porcine aortic bioprostheses.Ann Thorac Surg. 1990; 50: 817-819Abstract Full Text PDF PubMed Scopus (13) Google Scholar32 M23-mm C-E2 1/2……No surgical intervention; dead70 M27-mm C-E3……Bioprosthesis; aliveAmidi et al7Amidi M Ferson PF Labuda MJ Melhem MS Early manifestation of noncalcific aortic stenosis after porcine valve replacement.Ann Thorac Surg. 1990; 49: 471-472Abstract Full Text PDF PubMed Scopus (4) Google Scholar57 M25-mm C-E3Sodium warfarinDiabetes mellitusMedtronic-Hall; aliveCurrent report73 F23-mm C-E2 1/2……Medtronic-Hall; alive67 M23-mm C-E2……Medtronic-Hall; alive* C-E = Carpentier-Edwards. Open table in a new tab Penetration of plasma proteins into the valve substance and deposition of platelets and fibrin onto the surface of the bioprosthetic valve leaflets have been demonstrated as early as 2 to 3 days after valve replacement.8Spray TL Roberts WC Structural changes in porcine xenografts used as substitute cardiac valves.Am J Cardiol. 1977; 40: 319-330Abstract Full Text PDF PubMed Scopus (142) Google Scholar, 9Ferrans VJ Spray TL Billingham ME Roberts WC Structural changes in glutaraldehyde-treated porcine heterografts used as substitute cardiac valves: transmission and scanning electron microscopic observations in 12 patients.Am J Cardiol. 1978; 41: 1159-1184Abstract Full Text PDF PubMed Scopus (269) Google Scholar Although the incidence of clinically apparent thromboembolism related to deposits of fibrinoplatelets has been low, the accentuation of this process may conceivably result in the formation of a layer of thrombus that causes leaflet restriction and stenosis of the prosthesis. Whether anticoagulant or antiplatelet therapy will decrease the incidence of early thrombosis of aortic porcine bioprostheses is unclear. Of the 10 patients described in the literature (including the 2 in the current report) with early thrombosis of an aortic porcine bioprosthesis, only 2 received anticoagulant therapy; however, in 2 other patients,4Croft CH Buja LM Floresca MZ Nicod P Estrera A Late thrombotic obstruction of aortic porcine bioprostheses.Am J Cardiol. 1986; 57: 355-356Abstract Full Text PDF PubMed Scopus (9) Google Scholar the anticoagulant status was not stated. Because of the possible catastrophic consequences of unrecognized left ventricular outflow obstruction in conjunction with early thrombosis, some investigators have recommended anticoagulant therapy for all patients for 3 months after they have undergone aortic valve replacement with a porcine bioprosthesis.3Fishbein MC Gissen SA Collins Jr, JJ Barsamian EM Cohn LH Pathologic findings after cardiac valve replacement with glutaraldehyde-fixed porcine valves.Am J Cardiol. 1977; 40: 331-337Abstract Full Text PDF PubMed Scopus (114) Google Scholar, 7Amidi M Ferson PF Labuda MJ Melhem MS Early manifestation of noncalcific aortic stenosis after porcine valve replacement.Ann Thorac Surg. 1990; 49: 471-472Abstract Full Text PDF PubMed Scopus (4) Google Scholar In bioprosthetic valves in the aortic position, the incidence of thromboembolic episodes is probably greatest during the first 3 months after operation,10Chesebro JH Adams PC Fuster V Antithrombotic therapy in patients with valvular heart disease and prosthetic heart valves.J Am Coll Cardiol. 1986; 8: 41B-56BAbstract Full Text PDF PubMed Scopus (100) Google Scholar although not all investigators have confirmed this trend.11Joyce LD Nelson RM Comparison of porcine valve xenografts with mechanical prostheses: a 7 1/2 year experience.J Thorac Cardiovasc Surg. 1984; 88: 102-113PubMed Google Scholar Nevertheless, short-term anticoagulation with sodium warfarin for 3 months postoperatively seems prudent in patients with aortic porcine bioprostheses, particularly those who have had episodes of postoperative atrial arrhythmias or who have poor left ventricular function and low cardiac output. We recommend that anticoagulant therapy be maintained at an international normalized ratio of 2.0 to 3.0;12Hirsh J Poller L Deykin D Levine M Dalen JE Optimal therapeutic range for oral anticoagulants.Chest. 1989; 95: 5S-11SPubMed Scopus (129) Google Scholar however, because many patients who undergo aortic valve replacement are elderly and frail, complete anticoagulant therapy in some such patients may be inappropriate in consideration of the possible risk of anticoagulant-related hemorrhage. Therefore, the recommendation for routine anticoagulant therapy should be individualized on the basis of the patient's age and the adequacy of supervision. Thrombosis may occur in porcine bioprosthetic valves within 2 to 3 months after implantation. The initial manifestations are typical symptoms of left ventricular outflow obstruction, and these symptoms may be erroneously attributed to left ventricular dysfunction. Two-dimensional echocardiography with color flow Doppler analysis is an extremely useful noninvasive diagnostic tool for such patients. These patients need to undergo prompt assessment, and the prosthesis may need to be replaced.