Antiplatelet Therapy for Long-Term Management of Patients with Mechanical Aortic Prostheses.

BACKGROUND: A mechanical aortic prosthesis (MAP) may cause platelet activation secondary to shear forces, and the release of adenosine diphosphate (ADP). This platelet-mediated event may lead to arterial embolism. Traditionally, warfarin has been used to treat such cases, although this anticoagulant has no inhibitory effects on platelets. The study aim was to determine if antiplatelet agents could prevent thromboembolic events in patients with a MAP. METHODS: Since 2001, a total of 265 patients (average age 64.5 ± 12.0 years), each of whom received a MAP with or without additional aortic surgery, was followed at the authors' institution. Patients received a loading dose of clopidogrel or prasugrel + asprin 325 mg and tested for platelet inhibition. The maintenance dose was 75 mg clopidogrel or 10 mg prasugrel + 81 mg aspirin. Platelet reactivity was tested, using two different methods, after one month and at six-month intervals thereafter. RESULTS: The average follow up was 47.3 ± 44.3 months; total follow up was 11,688.8 months [974 patient-years (pt-yr)]. Over a 16-year period 51 patients died, primarily from myocardial infarction. Twelve patients had strokes (1.2%/pt-yr); of these patients, 10 had discontinued the antiplatelet medication (and were receiving warfarin). One patient was nonresponsive to clopidrogel and another (a compliant patient) was never tested. Strokes were not observed in compliant patients who responded to antiplatelet agents. Thirteen patients had gastrointestinal bleeding, four required transfusion, and three died due to cerebral aneurysms. CONCLUSIONS: Platelet-mediated thromboembolism following MAP installation can be treated with antiplatelet agents. The 16-year results of the present study suggested that antiplatelet agents can reduce thromboembolic events in patients with MAP. Strokes can be prevented in patients with MAP if treated with the correct antiplatelet agent, if the patient responds to the agent employed and is strictly compliant.

Carotid endarterectomy in the era of endovascular therapy: still the gold standard.

BACKGROUND: Carotid stenosis is the most common cause of ischemic stroke and is managed by carotid endarterectomy. We report our ten-year results of carotid surgery for stenosis and kinking of the internal carotid artery (ICA). METHODS: Four hundred sixty nine patients underwent surgery: 306 localized carotid endarterectomy, 107 extensive endarterectomy, 18 shortening of the ICA plus endarterectomy, 42 endarterectomy plus coronary artery bypass, 11 endarterectomy plus bypass to another cervical artery, and 1 endarterectomy with aortic valve replacement. RESULTS: Three patients had an ipsilateral stroke, 2 due to technical reasons and one for a stroke in evolution. Six had transient facial nerve dysfunction, 2 division of the hypoglossal nerve and one vocal cord paralysis. Thirty-one patients died, 16 during the hospital stay and 15 during the follow up. CONCLUSIONS: The short and long-term results of carotid endarterectomy are excellent. Carotid endarterectomy remains the "gold standard" for the treatment of carotid stenosis.

The "crush and aspiration" technique for debridement of the aortic annulus revisited.

An effective technique for the debridement of the aortic annulus using a needle holder to crush the calcify nodules, follow by the immediate aspiration of the pulverized material using a Yankauer suction device is reported.

Initial experience with dual antiplatelet thromboprophylaxis using clopidogrel and aspirin in patients with mechanical aortic prostheses.

BACKGROUND AND AIM OF THE STUDY: The aortic mechanical prosthesis (AMP) generates shear stress and causes erythrocyte fragmentation with ADP release that leads to platelet activation, the cause of thromboembolism. Thromboprophylaxis with the antiplatelet agents clopidogrel and aspirin (Clop-ASA) should reduce thromboembolic events in patients receiving an AMP. METHODS: Over an eight-year period at the authors' institutions, a total of 135 patients underwent aortic valve replacement (AVR), with or without concomitant thoracic aortic procedures, and received Clop-ASA as thromboprophylaxis. Platelet reactivity was measured using the Verify Now system. Thromboelastography was commenced in August 2006, and patients were followed at six-month intervals, with echocardiography and assessment of platelet reactivity. RESULTS: The total follow up was 4,776 months (equivalent to 398 patient-years (pt-yr)); the average follow up was 35.4 +/- 25 months. During follow up, 18 patients (13.3%) died, eight from coronary artery disease and three from valve-related causes. Five patients (3.7%; 1.2%/pt-yr) had bleeding complications, but none experienced valve thrombosis. Two patients (1.5%; 0.5%/pt-yr) had a transient ischemic attack (TIA); one of these occurred in a patient who discontinued Clop-ASA, and the other in a responder to Clop-ASA. Seven patients (5.2%; 1.7%/pt-yr) had strokes, one of which occurred at 48.5 months after AVR. Of the remaining six patients who had a stroke, one was a non-responder to clopidogrel and five had stopped taking Clop-ASA. The incidence of strokes before using the Accumetrics and TEG devices was 2.5% per pt-yr, but only 1.0% per pt-yr thereafter. CONCLUSION: Thromboprophylaxis in patients with AMP receiving Clop-ASA seems to be effective. Patients had a low incidence of bleeding, TIA and ischemic stroke, and no valve thrombosis. The use of assays to determine platelet reactivity helped to identify those patients who were resistant to clopidogrel, hyporesponders, and poorly compliant patients. Notably, the incidence of strokes after implementing assays to monitor platelet reactivity was reduced. Deaths were due primarily to myocardial infarction, and none of the deaths was anticoagulant-related. Patients receiving Clop-ASA should undergo routine testing of platelet reactivity, and also continue antiplatelet therapy so as to reduce the risk of ischemic stroke.

Short- and long-term efficacy of aspirin and clopidogrel for thromboprophylaxis for mechanical heart valves: an in vivo study in swine.

OBJECTIVE: In the interest of exploring alternatives to warfarin, we tested the hypothesis that clopidogrel combined with aspirin is effective for thromboprophylaxis of mechanical valves using a swine model. METHODS: Adult swine underwent heterotopic implantation of a modified bileaflet mechanical valved conduit bypassing the ligated, native descending thoracic aorta. Animals were randomized to no anticoagulation (n = 7), 175 U/kg dalteparin administered subcutaneously twice daily (n = 9), 325 mg of aspirin (n = 6), 75 mg of clopidogrel (n = 6), or 325 mg of aspirin and 75 mg of clopidogrel daily (n = 6) and survived for 30 days. Additionally, 11 animals were randomized to no anticoagulation (n = 5) or 325 mg of oral aspirin and 75 mg of clopidogrel daily (n = 6) and survived for 150 days. RESULTS: At 30 days, we observed 216 +/- 270 mg of thrombus for the no anticoagulation group, 53 +/- 91 mg for the dalteparin group, 33 +/- 23 mg for the aspirin group, 25 +/- 10 mg for the clopidogrel group, and 17 +/- 9 mg for the combined aspirin and clopidogrel group, respectively (P < .01 for clopidogrel and aspirin vs no anticoagulation). At 150 days, we observed 223 +/- 200 mg of thrombus for the no anticoagulation group and 4 +/- 4 mg for the aspirin and clopidogrel group (P = .02). Mean platelet deposition on the valve was 4.1 x 10(9) +/- 3.6 x 10(9) for the no anticoagulation and 6.81 x 10(7) +/- 1.4 x 10(8) for the combined aspirin and clopidogrel groups, respectively (P = .03). No major hemorrhagic events were observed. CONCLUSIONS: Effective short- and long-term thromboprophylaxis of mechanical valves can be achieved by using dual-antiplatelet therapy in this porcine model. Prospective human trials should be conducted with combination aspirin and clopidogrel as an alternative to warfarin in patients with bileaflet mechanical aortic valves.

Tricuspid anterior leaflet replacement with autologous pericardium and polytetrafluoroethylene chordae, followed by edge-to-edge repair.

Treatment of endocarditis of the tricuspid valve is very complex. Valvectomy without replacement can result in significant postoperative morbidity, and replacement is hazardous due to the possibility of prosthetic infection. Repair of the tricuspid valve is the best alternative. Many ingenious methods have been devised to repair the tricuspid valve in patients with infective endocarditis. However, repair of the endocarditic anterior leaflet presents a difficult surgical problem. We have developed a technique to replace the central portion of the anterior leaflet, in which most of the leaflet is excised and replaced with autologous pericardium. By preserving a small rim of the leaflet, we preserve the lateral and medial chordal attachments. Supplemental neochordae are created with polytetrafluoroethylene sutures. An edge-to-edge repair is used to correct residual insufficiency of the valve. We have used this technique in 4 patients. One patient died 1 month after surgery, but with a competent tricuspid valve. Three patients are now alive, 48, 34, and 1.5 months after surgery. Their tricuspid valves are functional, moving well, and competent. We conclude that the centrally infected anterior leaflet of the tricuspid valve can be replaced with autologous pericardium. The implantation of polytetrafluoroethylene neochordae and edge-to-edge repair can be used to achieve valve competence. Short- and medium-term follow-up in patients who have been treated with these techniques demonstrates that the valve remains fully mobile and competent.

Surgical treatment of multiple intracardiac and pulmonary artery tumor implants embolic from uterine intravascular leiomyomatosis.

Intravenous uterine leiomyomatosis is the invasion of the para-uterine veins by bundles of benign uterine muscle. These muscle bundles can grow and extend directly to pelvic organs or embolize to the right cardiac chambers or pulmonary artery. We report a patient who presented with two large mobile atrial masses that were seen on echocardiography. She was treated by excision of a 18cm mass from the right atrium, two masses from the right ventricle and a huge mass from the pulmonary artery. The tricuspid valve that was rendered insufficient, was repaired by the creation of PTFE neo chordae. Two weeks later a massively enlarged uterus, ovaries, a paracolic and three intraluminal masses in the inferior vena cava were removed. The patient recovered well. One year after surgery she was asymptomatic and no masses are seen in her echocardiogram. The tricuspid valve was competent. Patients presenting with cardiac tumors from intravenous uterine leiomyomatosis must undergo aggressive surgical management to achieve a cure. We recommend a two stage (thoracic and abdominal) approach.

Surgical treatment of right coronary arteries with anomalous origin and slit ostium.

BACKGROUND: Right coronary arteries arising in the left sinus or ectopically in the anterior coronary sinus with slit ostium course inside the aorta. They are subject to variable systolic compression and can cause myocardial ischemia with its sequelae or death. METHODS: From May 1991 to March 2003, we treated 16 patients with anomalous origin of the right coronary artery from the left sinus and 4 whose right coronary artery arose ectopically in the anterior sinus. All patients had a slit ostium and underwent transaortic unroofing of the trunk to modify the proximal portion of the anomalous artery. RESULTS: All patients survived operation, although 1 patient died of unrelated causes. Nineteen patients were followed for a period from 0.2 to 11.8 years (median age, 53 years). One experienced angina 1 year after surgery and underwent percutaneous transluminal coronary angioplasty of a left internal thoracic to left anterior descending coronary artery anastomosis. All patients are New York Heart Association class I, without angina; none has sustained a myocardial infarction or required reoperation. CONCLUSIONS: Right coronary arteries that arise in anomalous fashion with a slit ostium can cause myocardial ischemia or death. Transaortic modification of the anomalous trunk addresses the anatomic and pathophysiologic features of the malformation that cause myocardial ischemia. Excellent results can be achieved with this surgical approach.

Implantation of cryopreserved allograft pulmonary monocusp patch to treat nonthrombotic femoral vein incompetence.

We implanted cryopreserved allograft monocusp patches made from cadaveric pulmonary arteries to correct nonthrombotic valvular insufficiency of the common femoral vein in patients with chronic venous ulcers. Thirty-eight patients with 40 ulcers of longer than 3 years' duration underwent valvular repair of the common femoral vein from September 1995 through November 2001. We studied ulcer healing and competence of the monocusp patches using duplex ultrasonography Three patients with a total of 4 ulcers were lost to follow-up; therefore, 35 patients with 36 ulcers were available for examination. Twenty-four ulcers healed, and 12 did not. Of the 24 healed ulcers, 5 recurred. Four of the 5 ulcers were treated, 3 by monocusp patch replacement and 1 by iliac vein dilation and stenting. All such recurrent ulcers healed. The 5th recurrent ulcer was not treated, because the patient refused therapy Therefore, of the 24 ulcers that healed initially, 23 were healed at the end of the study Of the 12 unhealed ulcers, 4 were treated: 2 by ligation of incompetent perforating veins, 1 by saphenous vein ligation and partial stripping, and 1 by monocusp replacement. All 4 ulcers healed. The other 8 patients, all of whom had severe monocusp insufficiency, refused therapy. Therefore, of the 12 ulcers that did not heal initially, 4 were healed after additional treatment. No implanted monocusp patch developed clots. The ulcers remained healed when the prostheses remained competent. We conclude that monocusp patches can restore valvular competence to the femoral vein in patients who have primary valve insufficiency. In such patients, venous ulcers heal rapidly after prosthesis implantation if the monocusp remains competent and if there is no severe incompetence of the superficial venous system or of perforating veins.