Emergency coronary artery bypass surgery in the contemporary percutaneous coronary intervention era.

BACKGROUND: Since the advent of percutaneous coronary interventions (PCIs), technological advances, adjunctive pharmacotherapy, and increasing operator experience have contributed to lowering the occurrence of major complications. However, emergency coronary artery bypass surgery (CABG) for failed PCI is still associated with important morbidity and mortality, even in the era of coronary stenting. We sought to determine the prevalence, indications, predictors, and complications of emergency CABG after PCI in the past decade. METHODS AND RESULTS: We reviewed 18 593 PCIs performed from 1992 through 2000. There was a need for emergency CABG in 113 (0.61%) cases. The major indications were extensive dissection (n=61, 54%), perforation/tamponade (n=23, 20%), and recurrent acute closure (n=23, 20%). Prevalence of emergency CABG decreased from 1.5% of PCIs in 1992 to 0.14% in 2000 (P<0.001). Independent predictors of the need for emergency CABG included the worst ACC/AHA scoring of the intervened lesion (P<0.001) and female sex (P= 0.028), whereas history of prior bypass surgery and use of stents resulted in a decreased need for emergency CABG (P<0.001 for both). In patients undergoing emergency CABG, there were 17 (15%) in-hospital deaths, 14 (12%) perioperative Q-wave myocardial infarctions, and 6 (5%) cerebrovascular accidents. CONCLUSIONS: The need for emergency CABG has considerably decreased over time. Risk factors include female sex and a higher ACC/AHA score of the intervened lesion. However, morbidity and mortality of emergency CABG remain high even in the new millennium.

Importance of ablating all potential right atrial flutter circuits in postcardiac surgery patients.

OBJECTIVES: In patients with atrial flutter (AFL) and postoperative right atrial incisional scars, we sought to assess if the use of additional ablative lesions that targeted all potential re-entrant circuits, regardless of the presenting type of flutter, would prevent long-term recurrence. BACKGROUND: Patients with AFL and incisional scars have a complex atrial substrate that may promote multiple mechanisms of intra-atrial re-entry. METHODS: Twenty-nine patients with single right atrial incisional scars undergoing ablation for scar-dependent (n = 15) and cavotricuspid isthmus (CTI)-dependent (n = 14) flutter were studied. RESULTS: In the scar-dependent group, 9 of 15 (60%) patients had inducible or spontaneous CTI-dependent flutter immediately after ablation. In the group with CTI flutter, 7 of 14 (50%) patients had scar-related flutter immediately after ablation. If a second type of flutter was found during the initial ablation, a second ablation was performed either along the isthmus (scar-dependent group) or from the scar to another anatomic boundary (isthmus-dependent group). Patients were followed for 24 +/- 5 months and 18 +/- 6 months in the scar- and CTI-dependent groups, respectively. In the scar-dependent group, five of six (83%) who underwent only a single flutter line had recurrence at 3 +/- 1 months. In the isthmus-dependent group, three of seven (42%) patients who had only one flutter line performed had recurrence at 5 +/- 3 months. There was no flutter recurrence in patients who initially received two different flutter lines or in patients who subsequently underwent a second flutter line at follow-up. CONCLUSIONS: In patients with postoperative right atrial incisional scar and flutter, multiple ablation lines that target both scar-related and classic isthmuses appear necessary to prevent long-term recurrence.

The clinical challenge of bridging anticoagulation with low-molecular-weight heparin in patients with mechanical prosthetic heart valves: an evidence-based comparative review focusing on anticoagulation options in pregnant and nonpregnant patients.

BACKGROUND: Recent labeling changes for enoxaparin, a low-molecular-weight heparin (LMWH), have prompted a reexamination of its role in patients with mechanical prosthetic heart valves (MPHVs). Healthcare providers are faced with the challenge of weighing favorable trial results with LMWHs and balancing their clinical experiences with these agents as a bridge to oral anticoagulation in patients with prosthetic heart valves. This review will provide evidence-based guidance on issues surrounding the use of LMWH that require bridging anticoagulant therapy in the setting of cardiac surgery (MPHVs), cardiovascular disease, and during temporary interruption of oral anticoagulants in patients requiring periprocedural bridging therapy. METHODS: A Medline search was conducted of articles appearing in the medical literature published in English between 1992 and 2004. Approximately 120 clinical trials, case reports, editorials, and/or guideline statements were retrieved and reviewed by the authors as to their relevance for the subject under review, ie, bridging anticoagulation in patients with MPHVs. Approximately 80 of these publications were selected for detailed review, analysis, and discussion in a consensus format. RESULTS: This review addresses the controversy surrounding the divergence between the new labeling recommending against the use of LMWH in patients with MPHVs as well as the ongoing clinical experience and evidence in the medical literature. The clinical challenges in the use of LMWH and unfractioned heparin (UFH) in pregnant patients with MPHVs are presented; the evidence for LMWHs in nonpregnant patients with prosthetic valves is described; and the role of LMWH for bridging immediately after mechanical valve surgery and its periprocedural and perioperative uses are discussed. Based on an expert consensus panel, clinical algorithms for the use of LMWH in pregnant and nonpregnant patients with MPHVs are also illustrated. CONCLUSIONS: Based on the available data sets, clinical trials, reviews, and registry data, the evidence suggests that LMWH compared to UFH may be a safe and effective agent in patients with MPHVs. Future large-scale, randomized trials are warranted.

Comparison of outcomes in patients undergoing coronary bypass of patent versus restenosed bare metal stented coronary arteries.

It is unclear whether bypass of a patent stented artery affects clinical outcomes. We sought to compare the survival of patients who, as part of multisystem coronary artery bypass grafting, underwent revascularization of arteries with patent stents (<50% stenosis) or in-stent restenosis (>50% diameter stenosis). Of 550 consecutive patients with previously placed stents who underwent coronary artery bypass grafting from May 1995 to October 2003, we studied 399 who had only 1 stented vessel bypassed at surgery. Of these, 128 had coronary bypass to an artery with a patent stent and 271 had bypass to an artery with in-stent restenosis. Nonparametric survival estimates were obtained using the Kaplan-Meier method. A propensity-adjusted multivariate hazard model of group differences was generated using variables identified by bootstrap bagging. The unadjusted survival rate at 1 month, 1 year, and 5 years was 99.7%, 97.3%, and 89.1%, respectively, for the patent stent group and 96.6%, 93.9%, and 86.2%, respectively, for the in-stent restenosis group, a result of high early risk in the latter group. After adjusting for clinical variables, neither stent patency (p = 0.9) nor interval (p = 0.3) from stent placement was a risk factor, although advanced age, increased blood urea nitrogen, and preoperative atrial fibrillation were associated with poorer survival. In conclusion, survival after bypassing a patent stented coronary artery is comparable to that after bypassing a stented restenotic coronary artery.

Relation of albumin/creatinine ratio to C-reactive protein and to the metabolic syndrome.

We hypothesized that the association of high sensitivity C-reactive protein (CRP) with urinary albumin excretion (UAE) is predominately mediated through its correlation with the metabolic syndrome. Serum CRP and urine albumin:creatinine ratios (ACR) from 720 preventive cardiology patients were analyzed to estimate age- and gender-adjusted relative risk of high CRP and metabolic syndrome for high ACR. These data demonstrate that CRP independently predicts the presence of UAE, a marker of endothelial dysfunction.

Dysregulation of endogenous carbon monoxide and nitric oxide production in patients with advanced ischemic or nonischemic cardiomyopathy.

Carbon monoxide (CO) and nitric oxide (NO) are endogenous vasoregulatory molecules whose role in heart failure is not fully known. Exhaled CO and NO measurement provide novel noninvasive assessment of their endogenous production. We compared exhaled CO and NO in 24 patients with advanced ischemic and nonischemic cardiomyopathy and in 13 control subjects without known cardiac disease at rest and at 1 and 5 minutes after exercise testing. Exhaled CO was lower in patients with cardiomyopathy at rest (1.66 +/- 0.2 vs 1.80 +/- 0.5 ppm, p = 0.02) and 1 minute after exercise (1.35 +/- 0.2 vs 1.81 +/- 0.5 ppm, p = 0.009), with a similar trend at 5 minutes after exercise (1.45 +/- 0.3 vs 1.81 +/- 0.5 ppm, p = 0.14). Exhaled CO decreased in patients with cardiomyopathy after exercise (p <0.001 and p = 0.02 at rest vs 1 and 5 minutes after exercise, respectively) but was maintained in controls. Exhaled NO did not differ between patients with cardiomyopathy and controls at rest (9.48 +/- 1.4 vs 9.68 +/- 1.5 ppb, p = NS) and after exercise (1 minute: 10.91 +/- 1.8 vs 9.19 +/- 1.2 ppb; 5 minutes: 10.52 +/- 1.5 vs 8.90 +/- 1.2 ppb, p = NS). Exhaled NO increased after exercise in patients with cardiomyopathy (p = 0.01 and p = 0.04 rest vs exercise at 1 and 5 minutes, respectively), but was maintained in controls. Exhaled CO and NO were not correlated with peak oxygen consumption in patients with cardiomyopathy. The differential responses in exhaled CO and NO at rest or with exercise between patients with cardiomyopathy and normal controls may point to dysregulation in endogenous CO and NO production.

Relation of homocysteine and C-reactive protein to urinary albumin loss.

This study shows that elevated high-sensitivity C-reactive protein and plasma total homocysteine contribute independently to the likelihood of an increased urinary albumin:creatinine ratio. This result suggests that total homocysteine and C-reactive protein may be acting by separate mechanistic pathways.

Usefulness of plasma vitamin B(6), B(12), folate, homocysteine, and creatinine in predicting outcomes in heart transplant recipients.

Atherothrombotic complications are frequently seen in patients undergoing heart transplantation. These patients have high plasma total homocysteine concentrations associated with lower folate and vitamin B(6) levels. The relation between these metabolic abnormalities and the development of vascular complications, however, remains unclear. Fasting plasma total homocysteine, folate, vitamin B(12), vitamin B(6), and creatinine were measured in 160 cardiac transplant recipients who were followed for a mean duration of 28 +/- 9 months after blood draw (mean 59 +/- 28 months after transplant). Cardiovascular events and causes of mortality were determined and Cox proportional-hazards regression analysis was used to identify the independent predictors for cardiovascular events and mortality. Twenty-five patients developed cardiovascular events and 17 died (11 cardiovascular deaths). Mean +/- SD total homocysteine value was 18.4 +/- 8.5 (range 4.3 to 63.5 micromol/L). Hyperhomocysteinemia (> or =15 micromol/L) was seen in 99 patients (62%). Levels were no different in patients with or without cardiovascular complications/death (16.8 +/- 6.2 vs 18.9 +/- 9 micromol/L, p = 0.4). However, vitamin B(6) deficiency was seen in 21% of recipients with and in 9% without cardiovascular complications/death (p = 0.05). The relative risk for cardiovascular events, including cardiovascular death, increased 2.7 times (confidence interval 1.2 to 5.9) for B(6) levels < or =20 nmol/L compared with those with normal B(6) levels (p = 0.02). Thus, hyperhomocysteinemia is common in transplant recipients but may have no causal role in the atherothrombotic vascular complications of transplantation. Deficiency of vitamin B(6), however, may predict adverse outcomes, suggesting a possible role for supplementation with this vitamin.

Association of an abnormal exercise heart rate recovery with pulmonary function abnormalities.

BACKGROUND: Heart rate recovery (HRR) after exercise correlates with decreased vagal tone and mortality. Patients with COPD may have altered autonomic tone. We sought to determine the association of HRR with spirometry measures of pulmonary function. METHODS: We analyzed 627 patients (mean [+/- SD] age, 58 +/- 12 years; 65% men; mean FEV(1), 2.6 +/- 0.9 L, 80 +/- 20% predicted; patients receiving inhaled beta(2) agonist therapy, 10%; patients receiving inhaled anticholinergic therapy, 3%; patients receiving inhaled steroids, 5%; patients receiving oral prednisone, 4%) who had undergone maximal exercise testing and had undergone pulmonary function tests < 1 year apart. Patients with heart failure, pacemakers, and atrial fibrillation were excluded. Abnormal HRR was defined as a fall in heart rate during the first minute after exercise of

Low-molecular-weight-heparins as periprocedural anticoagulation for patients on long-term warfarin therapy: a standardized bridging therapy protocol.

BACKGROUND: Over 2 million patients in North America are on warfarin anticoagulation therapy for prevention of thromboembolism. Suspension of warfarin therapy is often required to prepare patients for invasive procedures or surgeries. To protect these patients against thromboembolism while they are off warfarin, shorter-acting parenteral agents such as low-molecular-weight heparins (LMWHs) are often used. We conducted a retrospective observational study of our anticoagulation clinic patients to assess the safety and efficacy of LMWHs using a standardized protocol for periprocedural anticoagulation therapy. METHODS: We included 69 consecutive patients who required interruption of their long-term warfarin therapy between August 2001 and August 2002, and were deemed by the treating physician to be at high enough risk for perioperative thromboembolism to justify bridging anticoagulation. We used a standard bridging therapy protocol in our anticoagulation clinic. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death. RESULTS: There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site. CONCLUSIONS: LMWH administration using our standard outpatient bridging protocol for perioperative anticoagulation appears to be relatively safe and efficacious, offering an alternative to inpatient administration of intravenous unfractionated heparin (UFH). Our study provides additional evidence to the limited published observational data regarding the safety and efficacy of LMWH as bridging therapy in the perioperative and periprocedural setting. Large, multicenter, randomized controlled trials are necessary to fully assess the safety and efficacy of LMWH for perioperative anticoagulation.We conducted a retrospective observational study of 69 consecutive anticoagulation clinic patients on warfarin between August 2001 and August 2002, who were undergoing a procedure or surgery. The study was done to assess the safety and efficacy of an outpatient LMWH bridging protocol. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 3 days preoperatively and 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death. There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site.