Background— Data regarding long-term outcomes after the arterial switch operation for D-transposition of the great arteries are scarce. Methods and Results— A single-institution retrospective cohort study was conducted to assess cardiovascular outcomes after an arterial switch operation between 1983 and 1999. Patients without follow-up visits within 3 years were contacted and secondary sources of information obtained. Overall, 400 patients, 154 (38.3%) with a ventricular septal defect, 238 (59.5%) with an intact septum, and 9 (2.3%) with a Taussig-Bing anomaly, were followed for a median of 18.7 years. In perioperative survivors, overall and arrhythmia-free survival rates at 25 years were 96.7±1.8% and 96.6±0.1%, respectively. Late mortality was predominantly a result of sudden deaths and myocardial infarction. At 25 years, 75.5±2.5% remained free from surgical or catheter-based reintervention. Freedom from an adverse cardiovascular event was 92.9±1.9% at 25 years. Independent predictors were a single right coronary artery (hazard ratio, 4.58; 95% confidence interval, 1.32-15.90), P =0.0166) and postoperative heart failure (hazard ratio, 6.93; 95% confidence interval, 1.57-30.62; P =0.0107). At last follow-up, the left ventricular ejection fraction was 60.3±8.9%, 97.3% had class I symptoms, and 5.2% obstructive coronary artery disease. Peak oxygen uptake was 35.1±7.6 mL/kg/min (86.1±15.1% predicted), with a chronotropic index <80% in 34.2%. At least moderate neoaortic and pulmonary regurgitation were present in 3.4% and 6.6%, respectively, and more than mild neoaortic and pulmonary stenosis in 3.2% and 10.3%. Conclusions— Long-term and arrhythmia-free survival is excellent after arterial switch operation. Although sequelae include chronotropic incompetence and neoaortic, pulmonary, and coronary artery complications, most patients maintain normal systolic function and exercise capacity.

Background Pulmonary hypertension (PH) has diverse causes with heterogeneous physiology compelling distinct management. Differentiating patients with primarily elevated pulmonary vascular resistance (PVR) from those with PH predominantly due to elevated left sided filling pressure is critical. Methods and Results We reviewed hemodynamics, echocardiography, and clinical data for 108 patients seen at a referral PH clinic with transthoracic echocardiogram and right heart catheterization within 1 year. We derived a simple echocardiographic prediction rule to allow hemodynamic differentiation of PH due to pulmonary vascular disease (PHPVD, defined as pulmonary artery wedge pressure (PAWP) ≤ 15mmHg and PVR >3WU). Age averaged 61.3±14.8 years, μPAWP and PVR were 16.4±7.1mmHg and 6.3±4.0WU respectively, and 52 (48.1%) patients fulfilled PHPVD hemodynamic criteria. The derived prediction rule ranged from −2 to +2 with higher scores suggesting higher probability of PHPVD: +1 point for left atrial AP dimension<3.2cm; +1 for presence of a mid-systolic notch or acceleration time<80msec; −1 for lateral mitral E:e′>10; −1 for left atrial AP dimension>4.2cm. PVR increased stepwise with score (for −2, 0 and +2, μPVR were 2.5, 4.5, and 8.1WU) while the inverse was true for PAWP (corresponding μPAWP were 21.5, 16.5 and 10.4mmHg). Among subjects with complete data, the score had an AUC of 0.921 for PHPVD. A score ≥ 0 had 100% sensitivity and 69.3% positive predictive value for PHPVD, with 62.3% specificity. No patients with a negative score had PHPVD. Patients with a negative score and acceleration time >100msec had normal PVR (μPVR=1.8WU, range=0.7–3.2WU). Conclusions We present a simple echocardiographic prediction rule that accurately defines PH hemodynamics facilitates improved screening and focused clinical investigation for PH diagnosis and management.

In adults with Fontan surgery, exercise test data can identify patients at increased risk of midterm morbidity and mortality.

Background Exercise capacity following Fontan surgery is often depressed. An inability to reduce pulmonary vascular resistance appropriately during exercise may contribute to this phenomenon. The aim of this study was to determine whether administration of iloprost, a selective pulmonary vasodilator, would improve exercise function after Fontan procedure. Methods Double-blind, randomized, placebo controlled, crossover trial. Patients performed two cardiopulmonary exercise tests (CPX) separated by <1 month. A single nebulizer treatment (iloprost or placebo) was administered before each CPX. Results 18 patients aged 12–49 (median 17) yrs were recruited. Mild throat discomfort developed in 10/18 patients during iloprost administration; all but 1 were able to complete treatment. No symptoms developed during placebo treatments (p<0.001). Two additional patients did not complete CPX: one with atrial flutter; another with developmental issues that precluded adequate CPX. In the 15 remaining subjects oxygen pulse (a surrogate for forward stroke volume) at peak exercise was higher following iloprost (median increase 1.2 ml/beat; p<0.001). Peak VO2 also rose (median increase 1.3 ml/kg/min; p<0.04). Nine patients had peak VO2 <30 ml/kg/min; each of these patients had higher peak VO2 following iloprost. Only 3/6 patients with peak VO2 >30 ml/kg/min had higher peak VO2 following iloprost (p<0.04). Conclusions Iloprost improves the peak oxygen pulse and peak VO2 of patients with Fontan physiology and appears to be particularly beneficial among patients with impaired exercise function. Treatment is associated with minor side effects. These findings support the concept of pulmonary vasodilator therapy in Fontan patients with limited functional capacity.

Pulmonary hypertension is comprised of heterogeneous diagnoses with distinct hemodynamic pathophysiology. Identifying elevated pulmonary vascular resistance (PVR) is critical for appropriate treatment. We reviewed data for patients seen at referral PH clinics who underwent echocardiography and right heart catheterization within 1 year. We derived equations to estimate PVR based on the ratio of estimated pulmonary artery (PA) systolic pressure (PASPDoppler) to RVOT VTI. We validated these equations in a separate sample and compared them to a published model based on the ratio of transtricuspid flow velocity to RVOT VTI (Model 1, Abbas et al 2003). The derived models were: italicPVR=1.2×PASPRVOT VTI italicPVR=PASPRVOT VTI+30.2emitalicif notch present The cohort included 217 patients with mean PA pressure=45.3±11.9mmHg, PVR=7.3±5.0WU and PA wedge pressure=14.8±8.1mmHg; just over 1/3rd had PA wedge pressure >15mmHg (35.5%) and 82.0% had PVR>3WU. Model 1 systematically underestimated PVR, especially with high PVR. The derived models demonstrated no systematic bias. Model 3 correlated best with PVR (r=0.80 vs. 0.73 and 0.77 for Models 1 and 2 respectively). Model 3 had superior discriminatory power for PVR>3WU (AUC=0.946) and PVR>5WU (AUC=0.924), though all models discriminated well. Model 3 estimated PVR>3 was 98.3% sensitive and 61.1% specific for PVR>3WU (PPV=93%; NPV=88%). In conclusion, we present an equation to estimate PVR, using the ratio of PASPDoppler to RVOT VTI and a constant designating presence of RVOT VTI mid-systolic notching, which provides superior agreement with PVR across a wide range of values.

Introduction Cardiac implantable electronic device (CIED) infections are potentially preventable complications associated with high morbidity, mortality, and cost. A recently developed bio-absorbable antibacterial envelope (TYRX™-A) might prevent CIED infections in high-risk subjects. However, data regarding safety and efficacy have not been published. Methods and results In a single-center retrospective cohort study, we compared the prevalence of CIED infections among subjects with ≥2 risk factors treated with the TYRX™-A envelope (N=135), the non-absorbable TYRX™ envelope (N=353), and controls who did not receive an envelope (N=636). Infection was ascertained by individual chart review. The mean (95% confidence interval) number of risk factors was 3.08 (2.84 to 3.32) for TYRX™-A, 3.20 (3.07 to 3.34) for TYRX™, and 3.09 (2.99 to 3.20) for controls, P=0.3. After a minimum 300 days follow-up, the prevalence of CIED infection was 0 (0%) for TYRX™-A, 1 (0.3%) for TYRX™, and 20 (3.1%) for controls (P=1 for TYRX™-A versus TYRX™, P=0.03 for TYRX™-A versus controls, and P=0.002 for TYRX™ versus controls). In a propensity score-matched cohort of 316 recipients of either envelope and 316 controls, the prevalence of infection was 0 (0%) and 9 (2.8%), respectively, P=0.004. When limited to 122 TYRX™-A recipients and 122 propensity-matched controls, the prevalence of CIED infections was 0 (0%) and 5 (4.1%), respectively, P=0.024. Conclusions Among high-risk subjects, the TYRX™-A bio-absorbable envelope was associated with a very low prevalence of CIED related infections that was comparable to that seen with the non-absorbable envelope.

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