Effect of Continuous Electrocardiogram Monitoring on Detection of Undiagnosed Atrial Fibrillation After Hospitalization for Cardiac Surgery: A Randomized Clinical Trial.

Importance: Postoperative atrial fibrillation (POAF) occurring after cardiac surgery is associated with adverse outcomes. Whether POAF persists beyond discharge is not well defined. Objective: To determine whether continuous cardiac rhythm monitoring enhances detection of POAF among cardiac surgical patients during the first 30 days after hospital discharge compared with usual care. Design, Setting, and Participants: This study is an investigator-initiated, open-label, multicenter, randomized clinical trial conducted at 10 Canadian centers. Enrollment spanned from March 2017 to March 2020, with follow-up through September 11, 2020. As a result of the COVID-19 pandemic, enrollment stopped on July 17, 2020, at which point 85% of the proposed sample size was enrolled. Cardiac surgical patients with CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, prior stroke or transient ischemic attack, vascular disease, age 65-74 years, female sex) score greater than or equal to 4 or greater than or equal to 2 with risk factors for POAF, no history of preoperative AF, and POAF lasting less than 24 hours during hospitalization were enrolled. Interventions: The intervention group underwent continuous cardiac rhythm monitoring with wearable, patch-based monitors for 30 days after randomization. Monitoring was not mandated in the usual care group within 30 days after randomization. Main Outcomes and Measures: The primary outcome was cumulative AF and/or atrial flutter lasting 6 minutes or longer detected by continuous cardiac rhythm monitoring or by a 12-lead electrocardiogram within 30 days of randomization. Prespecified secondary outcomes included cumulative AF lasting 6 hours or longer and 24 hours or longer within 30 days of randomization, death, myocardial infarction, ischemic stroke, non-central nervous system thromboembolism, major bleeding, and oral anticoagulation prescription. Results: Of the 336 patients randomized (163 patients in the intervention group and 173 patients in the usual care group; mean [SD] age, 67.4 [8.1] years; 73 women [21.7%]; median [interquartile range] CHA2DS2-VASc score, 4.0 [3.0-4.0] points), 307 (91.4%) completed the trial. In the intent-to-treat analysis, the primary end point occurred in 32 patients (19.6%) in the intervention group vs 3 patients (1.7%) in the usual care group (absolute difference, 17.9%; 95% CI, 11.5%-24.3%; P < .001). AF lasting 6 hours or longer was detected in 14 patients (8.6%) in the intervention group vs 0 patients in the usual care group (absolute difference, 8.6%; 95% CI, 4.3%-12.9%; P < .001). Conclusions and Relevance: In post-cardiac surgical patients at high risk of stroke, no preoperative AF history, and AF lasting less than 24 hours during hospitalization, continuous monitoring revealed a significant increase in the rate of POAF after discharge that would otherwise not be detected by usual care. Studies are needed to examine whether these patients will benefit from oral anticoagulation therapy. Trial Registration: ClinicalTrials.gov Identifier: NCT02793895.

Left Atrial Appendage Occlusion during Cardiac Surgery to Prevent Stroke.

BACKGROUND: Surgical occlusion of the left atrial appendage has been hypothesized to prevent ischemic stroke in patients with atrial fibrillation, but this has not been proved. The procedure can be performed during cardiac surgery undertaken for other reasons. METHODS: We conducted a multicenter, randomized trial involving participants with atrial fibrillation and a CHA2DS2-VASc score of at least 2 (on a scale from 0 to 9, with higher scores indicating greater risk of stroke) who were scheduled to undergo cardiac surgery for another indication. The participants were randomly assigned to undergo or not undergo occlusion of the left atrial appendage during surgery; all the participants were expected to receive usual care, including oral anticoagulation, during follow-up. The primary outcome was the occurrence of ischemic stroke (including transient ischemic attack with positive neuroimaging) or systemic embolism. The participants, research personnel, and primary care physicians (other than the surgeons) were unaware of the trial-group assignments. RESULTS: The primary analysis population included 2379 participants in the occlusion group and 2391 in the no-occlusion group, with a mean age of 71 years and a mean CHA2DS2-VASc score of 4.2. The participants were followed for a mean of 3.8 years. A total of 92.1% of the participants received the assigned procedure, and at 3 years, 76.8% of the participants continued to receive oral anticoagulation. Stroke or systemic embolism occurred in 114 participants (4.8%) in the occlusion group and in 168 (7.0%) in the no-occlusion group (hazard ratio, 0.67; 95% confidence interval, 0.53 to 0.85; P = 0.001). The incidence of perioperative bleeding, heart failure, or death did not differ significantly between the trial groups. CONCLUSIONS: Among participants with atrial fibrillation who had undergone cardiac surgery, most of whom continued to receive ongoing antithrombotic therapy, the risk of ischemic stroke or systemic embolism was lower with concomitant left atrial appendage occlusion performed during the surgery than without it. (Funded by the Canadian Institutes of Health Research and others; LAAOS III ClinicalTrials.gov number, NCT01561651.).

Effect of methylprednisolone on acute kidney injury in patients undergoing cardiac surgery with a cardiopulmonary bypass pump: a randomized controlled trial.

BACKGROUND: Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery. METHODS: We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007-2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 µmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery. RESULTS: Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease. INTERPRETATION: Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388.

International Expert Consensus on Sutureless and Rapid Deployment Valves in Aortic Valve Replacement Using Minimally Invasive Approaches.

OBJECTIVE: To define the benefit of sutureless and rapid deployment valves in current minimally invasive approaches in isolated aortic valve replacement. METHODS: A panel of 28 international experts with expertise in both minimally invasive aortic valve replacement and rapid deployment valves was constituted. After thorough literature review, the experts rated evidence-based recommendations in a modified Delphi approach. RESULTS: No guideline could be retrieved. Thirty-three clinical trials and 9 systematic reviews could be identified for detailed text analysis to obtain a total of 24 recommendations. After rating by the experts 12, final recommendations were identified: preoperative computed tomographic scan as well as intraoperative transesophageal echocardiography are highly recommended. Suitable annular sizes are 19 to 27 mm. There is a contraindication for bicuspid valves only for type 0 and for annular abscess or destruction due to infective endocarditis. The use of sutureless and rapid deployment valves reduces extracorporeal circulation and aortic cross-clamp time and leads to less early complications as prolonged ventilation, blood transfusion, atrial fibrillation, pleural effusions, paravalvular leakages and aortic regurgitation, and renal replacement therapy, respectively. These clinical outcomes result in reduced intensive care unit and hospital stay and reduced costs. The use of sutureless and rapid deployment valves will lead to a higher adoption rate of minimally invasive approaches in aortic valve replacement. Respect should be taken to a necessary short learning curve for both sutureless and minimally invasive programs. CONCLUSIONS: Sutureless and rapid deployment aortic valve replacement together with minimally invasive approaches offers an attractive option in aortic valve placement for patients requiring biological valve replacement.

Sutureless, rapid deployment valves and stented bioprosthesis in aortic valve replacement: recommendations of an International Expert Consensus Panel.

OBJECTIVES: After a panel process, recommendations on the use of sutureless and rapid deployment valves in aortic valve replacement were given with special respect as an alternative to stented valves. METHODS: Thirty-one international experts in both sutureless, rapid deployment valves and stented bioprostheses constituted the panel. After a thorough literature review, evidence-based recommendations were rated in a three-step modified Delphi approach by the experts. RESULTS: Literature research could identify 67 clinical trials, 4 guidelines and 10 systematic reviews for detailed text analysis to obtain a total of 28 recommendations. After rating by the experts, 12 recommendations were identified and degree of consensus for each was determined. Proctoring and education are necessary for the introduction of sutureless valves on an institutional basis as well as for the individual training of surgeons. Sutureless and rapid deployment should be considered as the valve prosthesis of first choice for isolated procedures in patients with comorbidities, old age, delicate aortic wall conditions such as calcified root, porcelain aorta or prior implantation of aortic homograft and stentless valves as well as for concomitant procedures and small aortic roots to reduce cross-clamp time. Intraoperative transoesophageal echocardiography is highly recommended, and in case of right anterior thoracotomy, preoperative computer tomography is strongly recommended. Suitable annular sizes are 19-27 mm. There is a contraindication for bicuspid valves only for Type 0 and for annular abscess or destruction due to infective endocarditis. Careful but complete decalcification of the aortic root is recommended to avoid paravalvular leakage; extensive decalcification should be avoided not to create annular defects. Proximal anastomoses of concomitant coronary artery bypass grafting should be placed during a single aortic cross-clamp period or alternatively with careful side clamping. Available evidence suggests that the use of sutureless and rapid deployment valve is associated with (can translate into) reduced early complications such as prolonged ventilation, blood transfusion, atrial fibrillation, pleural effusions and renal replacement therapy, respectively, and may result in reduced intensive care unit and hospital stay in comparison with traditional valves. CONCLUSION: The international experts recommend various benefits of sutureless and rapid deployment technology, which may represent a helpful tool in aortic valve replacement for patients requiring a biological valve. However, further evidence will be needed to reaffirm the benefit of sutureless and rapid deployment valves.

Methylprednisolone in patients undergoing cardiopulmonary bypass (SIRS): a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Cardiopulmonary bypass initiates a systemic inflammatory response syndrome that is associated with postoperative morbidity and mortality. Steroids suppress inflammatory responses and might improve outcomes in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass. We aimed to assess the effects of steroids in patients at high risk of morbidity and mortality undergoing cardiopulmonary bypass. METHODS: The Steroids In caRdiac Surgery (SIRS) study is a double-blind, randomised, controlled trial. We used a central computerised phone or interactive web system to randomly assign (1:1) patients at high risk of morbidity and mortality from 80 hospital or cardiac surgery centres in 18 countries undergoing cardiac surgery with the use of cardiopulmonary bypass to receive either methylprednisolone (250 mg at anaesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients were assigned with block randomisation with random block sizes of 2, 4, or 6 and stratified by centre. Patients aged 18 years or older were eligible if they had a European System for Cardiac Operative Risk Evaluation of at least 6. Patients were excluded if they were taking or expected to receive systemic steroids in the immediate postoperative period or had a history of bacterial or fungal infection in the preceding 30 days. Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcomes were 30-day mortality and a composite of death and major morbidity (ie, myocardial injury, stroke, renal failure, or respiratory failure) within 30 days, both analysed by intention to treat. Safety outcomes were also analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00427388. FINDINGS: Patients were recruited between June 21, 2007, and Dec 19, 2013. Complete 30-day data was available for all 7507 patients randomly assigned to methylprednisolone (n=3755) and to placebo (n=3752). Methylprednisolone, compared with placebo, did not reduce the risk of death at 30 days (154 [4%] vs 177 [5%] patients; relative risk [RR] 0·87, 95% CI 0·70-1·07, p=0·19) or the risk of death or major morbidity (909 [24%] vs 885 [24%]; RR 1·03, 95% CI 0·95-1·11, p=0·52). The most common safety outcomes in the methylprednisolone and placebo group were infection (465 [12%] vs 493 [13%]), surgical site infection (151 [4%] vs 151 [4%]), and delirium (295 [8%] vs 289 [8%]). INTERPRETATION: Methylprednisolone did not have a significant effect on mortality or major morbidity after cardiac surgery with cardiopulmonary bypass. The SIRS trial does not support the routine use of methylprednisolone for patients undergoing cardiopulmonary bypass. FUNDING: Canadian Institutes of Health Research.

Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

BACKGROUND: Antithrombotic therapy in valvular disease is important to mitigate thromboembolism, but the hemorrhagic risk imposed must be considered. METHODS: The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement. RESULTS: In rheumatic mitral disease, we recommend vitamin K antagonist (VKA) therapy when the left atrial diameter is > 55 mm (Grade 2C) or when complicated by left atrial thrombus (Grade 1A). In candidates for percutaneous mitral valvotomy with left atrial thrombus, we recommend VKA therapy until thrombus resolution, and we recommend abandoning valvotomy if the thrombus fails to resolve (Grade 1A). In patients with patent foramen ovale (PFO) and stroke or transient ischemic attack, we recommend initial aspirin therapy (Grade 1B) and suggest substitution of VKA if recurrence (Grade 2C). In patients with cryptogenic stroke and DVT and a PFO, we recommend VKA therapy for 3 months (Grade 1B) and consideration of PFO closure (Grade 2C). We recommend against the use of anticoagulant (Grade 1C) and antiplatelet therapy (Grade 1B) for native valve endocarditis. We suggest holding VKA therapy until the patient is stabilized without neurologic complications for infective endocarditis of a prosthetic valve (Grade 2C). In the first 3 months after bioprosthetic valve implantation, we recommend aspirin for aortic valves (Grade 2C), the addition of clopidogrel to aspirin if the aortic valve is transcatheter (Grade 2C), and VKA therapy with a target international normalized ratio (INR) of 2.5 for mitral valves (Grade 2C). After 3 months, we suggest aspirin therapy (Grade 2C). We recommend early bridging of mechanical valve patients to VKA therapy with unfractionated heparin (DVT dosing) or low-molecular-weight heparin (Grade 2C). We recommend long-term VKA therapy for all mechanical valves (Grade 1B): target INR 2.5 for aortic (Grade 1B) and 3.0 for mitral or double valve (Grade 2C). In patients with mechanical valves at low bleeding risk, we suggest the addition of low-dose aspirin (50-100 mg/d) (Grade 1B). In valve repair patients, we suggest aspirin therapy (Grade 2C). In patients with thrombosed prosthetic valve, we recommend fibrinolysis for right-sided valves and left-sided valves with thrombus area < 0.8 cm(2) (Grade 2C). For patients with left-sided prosthetic valve thrombosis and thrombus area ≥ 0.8 cm(2), we recommend early surgery (Grade 2C). CONCLUSIONS: These antithrombotic guidelines provide recommendations based on the optimal balance of thrombotic and hemorrhagic risk.

Randomized trial of fondaparinux versus heparin to prevent graft failure after coronary artery bypass grafting: the Fonda CABG study.

We sought to assess the feasibility of comparing the efficacy and safety of fondaparinux versus heparin for prevention of graft failure and major CV events in patients undergoing coronary artery bypass grafting (CABG). Patients undergoing CABG were randomized to receive postoperative injections of fondaparinux or heparin in-hospital. After discharge, the fondaparinux group received fondaparinux and the heparin group received placebo injections for 30 days post surgery. Efficacy outcomes were graft failure, death, MI, and stroke at 30 days. Safety outcomes were bleeding, transfusion, and reoperation. 100 patients were recruited, 99 were randomized, 49 received fondaparinux and 50 received heparin. CT angiography was performed in 97% of patients. 188 grafts in the treatment group and 189 grafts in the heparin group were imaged. A similar proportion of patients treated with fondaparinux compared with heparin had at least one occluded graft (18.8% fondaparinux vs. 14.9% heparin, P = 0.62) and a similar number of grafts were occluded in each treatment group (all grafts: 4.8% vs. 4.8%, P = 0.99; saphenous vein grafts 4.2% vs. 4.2%, P = 0.98). There was no difference between treatment groups in death, MI, stroke, bleeding events, or reoperation. One in 10 patients undergoing CABG had at least one occluded graft at 30 days and one in 20 grafts is occluded by 30 days. Fondaparinux appears to be a safe alternative to heparin after CABG and it is feasible to conduct a definitive RCT using CT angiography to evaluate the effect of fondaparinux treatment on graft patency.

Randomized trial of aspirin and clopidogrel versus aspirin alone for the prevention of coronary artery bypass graft occlusion: the Preoperative Aspirin and Postoperative Antiplatelets in Coronary Artery Bypass Grafting study.

BACKGROUND: Routine use of postoperative aspirin after coronary artery bypass grafting (CABG) reduces graft failure and cardiovascular events. The efficacy and safety of adding clopidogrel to aspirin for the prevention of graft failure and cardiovascular events after CABG are unknown. We performed a pilot study measuring safety and efficacy outcomes of aspirin and clopidogrel therapy after CABG. METHODS: We randomized 100 patients undergoing CABG to receive placebo or clopidogrel started after surgery and for 30 days. All patients received aspirin 81 mg daily. Graft patency was measured by cardiac computed tomography angiography at 30 days. RESULTS: Clinical follow-up was complete for 99 patients, and 79 (80%) underwent computed tomography angiography. The proportion of patients with ≥1 occluded graft was not significantly different between placebo and clopidogrel groups (9/39 [23.1%] vs 7/40 [17.5%], relative risk 0.95, 95% CI 0.80-1.14, P=.54). Among radial artery grafts, the placebo group had a significantly higher number of occlusions or "string signs" compared with the clopidogrel group (7/16 [43.8%] vs 2/19 [10.5%], relative risk 0.24, 95% CI 0.06-1.00, P=.05). There was no difference between placebo and clopidogrel groups in the safety outcomes of total postoperative bleeding, transfusions, bleeding events, and reexploration and in the efficacy outcomes of nonfatal myocardial infarction, stroke, and death. CONCLUSIONS: This pilot study confirms a high rate of graft occlusion after CABG surgery and suggests that the addition of clopidogrel to aspirin is feasible and safe and may be superior for prevention of graft failure in radial artery grafts.

The effect of pre-operative aspirin on bleeding, transfusion, myocardial infarction, and mortality in coronary artery bypass surgery: a systematic review of randomized and observational studies.

AIMS: To obtain estimates of the efficacy and safety of pre-operative aspirin in patients undergoing coronary artery bypass grafting (CABG). METHODS AND RESULTS: Eligible studies included randomized controlled trials (RCTs) and observational studies of patients undergoing CABG, comparing pre-operative aspirin with no aspirin/placebo, and reporting at least one of our primary outcomes. In eight RCTs (n = 805), pre-operative aspirin increased post-operative bleeding [Mean difference (MD), 104.9 mL; 95% confidence interval (CI), 19.2-190.6; P = 0.016] and reoperation [odds ratio (OR), 2.52; 95% CI, 1.18-5.38; P = 0.017), but not transfusion requirements (MD, 0.62 units; 95% CI, -0.06-1.30; P = 0.072). Subgroup analysis suggested that bleeding was increased with aspirin doses > or =325 mg/day, but not with lower doses. In 14 observational studies (n = 4485), pre-operative aspirin increased post-operative bleeding (MD, 113.6 mL; 95% CI, 45.2-182.0; P = 0.001) and transfusion requirements (MD, 0.34; 95% CI, 0.12-0.56 units; P = 0.002), but not reoperation (OR, 1.12; 95% CI, 0.69-1.83; P = 0.647). Neither analysis detected a significant effect on myocardial infarction or death. CONCLUSION: Pre-operative aspirin increases post-operative bleeding, but this may be avoided by the use of aspirin doses <325 mg/day. Most of the RCTs are old and the meta-analysis was underpowered for efficacy outcomes. A large randomized trial is necessary to determine the safety and efficacy of pre-operative aspirin in the setting of contemporary cardiac surgical practice.

Warfarin cessation before cardiopulmonary bypass: lessons learned from a randomized controlled trial of oral vitamin K.

BACKGROUND: No standard protocol of warfarin cessation and bridging for cardiac surgery exists. This study examined a single institution's protocol with respect to timing of cessation and low molecular weight heparin bridging. The recovery of vitamin K-dependent factors and the effects of cardiopulmonary bypass on coagulation factors were explored. Administration of preoperative oral vitamin K was investigated in a randomized, placebo-controlled trial. A post hoc analysis examined residual anti-Xa activity of enoxaparin bridging. METHODS: Forty patients on warfarin undergoing cardiopulmonary bypass were randomized to receive 5 mg of oral vitamin K or placebo 6 days before surgery. Blood samples were acquired at six times and assayed for prothrombin time, anti-Xa activity, and functional levels of factors II, V, VII, and IX and of protein C. Measures of bleeding and transfusion were also collected. RESULTS: No difference in bleeding or transfusion was observed between the treatment groups. Appropriate recovery of coagulation factors was observed with warfarin cessation irrespective of treatment group. The coagulation factors decreased by an average of 0.36 units/mL during the period of surgery. Enoxaparin 1 mg/kg until the evening before surgery resulted in 70% of patients entering the operating room with therapeutic anti-Xa activity (0.6 +/- 0.3 units/mL). CONCLUSIONS: The cessation of warfarin 6 days preoperatively is sufficient for functional recovery of vitamin K-dependent factors, which undergo significant changes during the operative course. A 5-mg dose of vitamin K with warfarin discontinuation did not enhance recovery of vitamin K-dependent factors and is unnecessary. With the observation that enoxaparin up until the night before surgery resulted in high residual anti-Xa levels in the operating room, our center now administers the last dose of enoxaparin 24 hours before surgery.

Can extra protamine eliminate heparin rebound following cardiopulmonary bypass surgery?

OBJECTIVES: Heparin rebound, the reappearance of anticoagulant activity after adequate neutralization with protamine, is thought to contribute to excessive postoperative bleeding after cardiac surgery. We have previously demonstrated that a significant amount of heparin is bound nonspecifically to plasma proteins and is incompletely neutralized by protamine. The aim of this study was to investigate whether clinically important bleeding attributable to heparin rebound can be eliminated by infusion of small amounts of additional protamine for 6 hours postoperatively and whether this treatment can reduce mediastinal blood loss. METHODS: Three hundred patients undergoing elective cardiac surgery were randomized to receive either a continuous infusion of protamine sulphate (25 mg/h for 6 hours) postoperatively or saline placebo. Serial blood samples were obtained to measure thrombin clotting time and anti-factor Xa activity. Heparin bound nonspecifically to plasma proteins was measured after displacement with a chemically altered heparin with low affinity to antithrombin. Mediastinal blood loss and transfusion requirements were recorded. RESULTS: Heparin rebound was demonstrated in every patient in the placebo group as reflected by increased thrombin clotting time, anti-factor Xa activity, and protein-bound heparin between 1 and 6 hours after surgery. In contrast, heparin rebound was eliminated in the protamine infusion group. The thrombin clotting time was normalized and both heparin concentration and protein-bound heparin were almost undetectable (P <.001). There was a modest 13% reduction in postoperative bleeding but this did not reduce blood transfusions. No adverse events were attributable to the extra protamine. CONCLUSIONS: Postoperative protamine infusion was able to almost totally abolish heparin rebound. In the context of this study, protamine infusion resulted in reduced postoperative bleeding but the magnitude was insufficient to alter transfusion requirements.

Warfarin-associated multiple digital necrosis complicating heparin-induced thrombocytopenia and Raynaud's phenomenon after aortic valve replacement for adenocarcinoma-associated thrombotic endocarditis.

Necrosis of the digits is a rare complication of warfarin therapy of obscure pathogenesis. We report a 61-year-old woman with a 12-month history of Raynaud's phenomenon who developed multiple digital necrosis following aortic valve replacement with mechanical prosthesis for aortic insufficiency caused by nonbacterial thrombotic endocarditis. Exacerbation of Raynaud's phenomenon occurred during the postoperative period, with daily episodes of ischemia of the fingers and toes that improved with local warming. However, coincident with the occurrence of immune heparin-induced thrombocytopenia, and while undergoing routine warfarin anticoagulation because of the mechanical valve prosthesis, the patient abruptly developed progression of digital ischemia to multiple digital necrosis on postoperative day 8, at the time the international normalized ratio reached its peak value of 4.3. All limb pulses were readily palpable, and vascular imaging studies showed thrombosis only in the superficial femoral and popliteal veins of the right leg. Coagulation studies showed greatly elevated levels of thrombin-antithrombin complexes and prothrombin fragment F1.2 levels, consistent with uncontrolled thrombin generation. After vitamin K administration, no abnormalities of the protein C anticoagulant pathway were identified, consistent with previous studies of other patients with warfarin-induced necrosis complicating heparin-induced thrombocytopenia. Subsequently, the patient was shown to have metastatic breast adenocarcinoma, which explained the patient's initial presentation with nonbacterial thrombotic endocarditis. This patient case suggests that multiple digital gangrene can result from the interaction of various localizing and systemic factors, including compromised microvascular blood flow (Raynaud's phenomenon), increased thrombin generation (heparin-induced thrombocytopenia, adenocarcinoma), and warfarin-induced failure of the protein C natural anticoagulant pathway.