Early on-Cardiopulmonary Bypass Hypotension and other Factors Associated with Vasoplegic Syndrome
 

Vasoplegic syndrome is a form of vasodilatory shock that can occur after cardiopulmonary bypass (CPB). We hypothesized that the severity and duration of the decline in mean arterial pressure immediately after CPB is begun can be used as a predictor of patients will develop vasoplegia in the immediate post-CPB period and of poor clinical outcome. Investigators quantified the decline in mean arterial pressure by calculating an area above the mean arterial blood pressure curve.

2823 adult cardiac surgery cases performed between July 2002 and December 2006 were retrospectively analyzed. Of these 2823, 577 (20.4%) were vasoplegic after separation from CPB. 1645 patients (58.3%) had a clinically significant decline in mean arterial pressure after starting CPB (area above the mean arterial blood pressure curve > 0) and were significantly more likely to become vasoplegic (23.0% versus 16.9%; odds ratio, 1.26; 95% confidence interval, 1.12 to 1.43; P < 0.001). These patients were also far more likely either to die in hospital or to have a length of stay > 10 days (odds ratio, 3.30; 95% confidence interval, 1.44 to 7.57; P = 0.005). Additional risk factors for developing vasoplegia that were identified included the additive euroSCORE, procedure type, prebypass mean arterial pressure, length of bypass, administration of pre-CPB vasopressors, core temperature on CPB, pre- and post-CPB hematocrit, the preoperative use of b-blockers or angiotensin-converting enzyme inhibitors, and the intraoperative use of aprotinin.

The results of this investigation suggest that it is possible to predict vasoplegia intraoperatively before separation from CPB and that the presence of a clinically significant area above the mean arterial blood pressure curve serves as a predictor of poor clinical outcome.

Circulation. 2009;120:1664-1671.

Determinants of Surgical Outcome in Patients with Isolated Tricuspid Regurgitation

Researchers sought to identify preoperative predictors of clinical outcomes after surgery in patients with severe tricuspid regurgitation.

Sixty-one consecutive patients (54 women, aged 57 ± 9 years) with isolated severe tricuspid regurgitation undergoing corrective surgery were prospectively enrolled. Twenty-one patients (34%) were in New York Heart Association functional class II, 35 (57%) in class III, and 5 (9%) in class IV. Fifty-seven patients (93%) had previous history of left-sided valve surgery. Preoperative echocardiography revealed pulmonary artery systolic pressure of 41.5 ± 8.7 mm Hg, right ventricular (RV) end-diastolic area of 35.1 ±9 .0cm2, and RV fractional area change of 41.3 ± 8.4%.

The median follow-up duration after surgery was 32 months (range, 12 to 70). Six of the 61 patients died before discharge; thus, operative mortality was 10%. Three of the 55 patients who survived surgery died during follow-up, and 6 patients required readmission because of cardiovascular problems. Thus, 46 patients (75%) remained event free at the end of follow-up. In the 54 patients who underwent 6-month clinical and echocardiographic follow-up, RV end-diastolic area decreased by 29%, with a corresponding 26% reduction in RV fractional area change. Thirty-three patients (61%) showed improved functional capacity after surgery.

On multivariable Cox regression analysis, preoperative hemoglobin level (P < 0.001) and RV end-systolic area (P < 0.001) emerged as independent determinants of clinical outcomes. On receiver operating characteristic curve analysis, we found that RV end-systolic area < 20cm2 predicted event-free survival with a sensitivity of 73% and a specificity of 67%, and a hemoglobin level > 11.3 g/dL predicted event-free survival with a sensitivity of 73% and a specificity of 83%.

Timely correction of severe tricuspid regurgitation carries an acceptable risk and improves functional capacity. Surgery should be considered before the development of advanced RV systolic dysfunction and before the development of anemia.


Circulation. 2009;120:1672-1678.

 

Atrial Arrhythmias in Adults with Congenital Heart Disease
 

Atrial arrhythmias increase disease burden in the general adult population. Adults with congenital heart lesions constitute a rapidly growing group of patients with cardiovascular disease. Investigators hypothesized that atrial arrhythmias increase with age and impair health outcomes in this population.

A population-based analysis of prevalence, lifetime risk, mortality, and morbidity associated with atrial arrhythmias in adults with congenital heart disease was conducted from l983 to 2005. In 38 428 adults with congenital heart disease in 2005, 5812 had atrial arrhythmias. Overall, the 20-year risk of developing atrial arrhythmia was 7% in a 20-year-old subject and 38% in a 50-year-old subject. More than 50% of patients with severe congenital heart disease reaching age 18 years developed atrial arrhythmias by age 65 years. In patients with congenital heart disease, the hazard ratio of any adverse event in those with atrial arrhythmias compared with those without was 2.50 (95% confidence interval, 2.38 to 2.62; P < 0.0001), with a near 50% increase in mortality (hazard ratio, 1.47; 95% confidence interval, 1.37 to 1.58; P < 0.001), more than double the risk of morbidity (stroke or heart failure) (hazard ratio, 2.21; 95% confidence interval, 2.07 to 2.36; P < 0.001), and 3 times the risk of cardiac interventions (hazard ratio, 3.00; 95% confidence interval, 2.81 to 3.20; P < 0.001).

Atrial arrhythmias occurred in 15% of adults with congenital heart disease. The lifetime incidence increased steadily with age and was associated with a doubling of the risk of adverse events. An increase in resource allocation should be anticipated to deal with this increasing burden.


Circulation. 2009;120:1679-1686.
 
 

Short-Term Hemodynamic Effects of Cardiac Resynchronization Therapy in Patients with Heart Failure, a Narrow QRS Duration, and no Dyssynchrony
 

Cardiac resynchronization therapy produces both short-term hemodynamic and long-term symptomatic/ mortality benefits in symptomatic heart failure patients with a QRS duration > 120ms. This is conventionally believed to be due principally to relief of dyssynchrony, although we recently showed that relief of external constraint to left ventricular filling may also play a role. Researchers evaluated the short-term hemodynamic effects in symptomatic patients with a QRS duration < 120ms and no evidence of dyssynchrony on conventional criteria and assessed the effects on contractility and external constraint.

Thirty heart failure patients (New York Heart Association class III/IV) with a left ventricular ejection fraction 35% who were in sinus rhythm underwent pressure-volume studies at the time of pacemaker implantation. External constraint, left ventricular stroke work, dP/dtmax, and the slope of the preload recruitable stroke work relation were measured from the end-diastolic pressure-volume relation before and during delivery of biventricular and left ventricular pacing. The following changes were observed during delivery of cardiac resynchronization therapy: Cardiac output increased by 25 ± 5%(P < 0.05), absolute left ventricular stroke work increased by 26 ± 5% (P < 0.05), the slope of the preload recruitable stroke work relation increased by 51 ± 15% (P < 0.05), and dP/dtmax increased by 9 ± 2% (P < 0.05). External constraint was present in 15 patients and was completely abolished by both biventricular and left ventricular pacing (P < 0.05).

Cardiac resynchronization therapy results in an improvement in short-term hemodynamic variables in patients with a QRS <120 ms. The mechanism is related to both contractile improvement and relief of external constraint. These findings provide a potential physiological basis for cardiac resynchronization therapy in this patient population.


Circulation. 2009;120:1687-1694.)


 

Bleeding Increases the Risk of Ischemic Events in Patients with Peripheral Arterial Disease
 

Patients with peripheral arterial disease are at high risk of ischemic events and therefore are treated with antithrombotics. In patients with coronary artery disease or cerebrovascular disease, bleeding is related to the subsequent occurrence of ischemic events. Investigators assessed whether this is also the case in patients with peripheral arterial disease.

All patients from the Dutch Bypass and Oral Anticoagulants or Aspirin (BOA) Study, a multicenter randomized trial comparing oral anticoagulants with aspirin after infrainguinal bypass surgery, were included. The primary outcome event was the composite of nonfatal myocardial infarction, nonfatal ischemic stroke, major amputation, and cardiovascular death. To identify major bleeding as an independent predictor for ischemic events, crude and adjusted hazard ratios with 95% confidence intervals were calculated with multivariable Cox regression models. From 1995 until 1998, 2650 patients were included with 101 nonfatal major bleedings. During a mean follow-up of 14 months, the primary outcome event occurred in 218 patients; 22 events were preceded by a major bleeding. The mean time between major bleeding and the primary outcome event was 4 months. Major bleeding was associated with a 3-fold increased risk of subsequent ischemic events (crude hazard ratio, 3.0; 95% confidence interval, 1.9 to 4.6; adjusted hazard ratio, 3.0; 95% confidence interval, 1.9 to 4.7).

In patients with peripheral arterial disease, as in patients with coronary artery disease or cerebrovascular disease, major bleeding was independently associated with major ischemic complications. Without compromising the benefits of antithrombotics, these findings call for caution relative to the risks of major bleeding.


Circulation. 2009;120:1569-1576.