Noninvasive estimation of pulmonary vascular resistance improves portopulmonary hypertension screening in liver transplant candidates.

Despite limitations in sensitivity and specificity, estimation of the pulmonary artery systolic pressure (ePASP) on echocardiography is used for portopulmonary hypertension (PoPH) screening in liver transplant (LT) candidates. We proposed that alternative echocardiographic models, such as estimated pulmonary vascular resistance (ePVR), may provide improved testing characteristics in PoPH screening. In a retrospective analysis of 100 LT candidates, we found that the formula ePVR = ePASP/VTIRVOT  + 3 if MSN (VTIRVOT  = right ventricular outflow tract time velocity integral; MSN = mid-systolic notching of the VTIRVOT Doppler signal) significantly improves accuracy of PoPH screening compared to ePASP. We determined the optimal ePVR cutoff for PoPH screening to be 2.76 Wood units, as this cutoff provided 100% sensitivity and 73% specificity in screening for clinically significant PoPH. Comparatively, ePASP at a cutoff of 40 mm Hg provided 91% sensitivity and 48% specificity. We devised a new screening algorithm based on the use of ePVR at intermediate ePASP values (35-54 mm Hg), and we confirmed the testing characteristics of this algorithm in a separate validation cohort of 50 LT candidates. In screening LT candidates for PoPH, the ePASP lacks accuracy, leading to unnecessary RHCs and undiagnosed cases of PoPH. A screening algorithm which incorporates the ePVR may be more reliable.

Echocardiographic estimation of pulmonary vascular resistance in advanced lung disease.

Noninvasive assessment of pulmonary hemodynamics is often performed by echocardiographic estimation of the pulmonary artery systolic pressure (ePASP), despite limitations in the advanced lung disease population. Other noninvasive hemodynamic variables, such as echocardiographic pulmonary vascular resistance (ePVR), have not been studied in this population. We performed a retrospective analysis of 147 advanced lung disease patients who received both echocardiography and right heart catheterization for lung transplant evaluation. The ePVR was estimated by four previously described equations. Noninvasive and invasive hemodynamic parameters were compared in terms of correlation, agreement, and accuracy. The ePVR models strongly correlated with invasively determined PVR and had good accuracy with biases of <1 Wood units (WU), although with moderate precision and wide 95% limits of agreement varying from 5.9 to 7.8 Wood units. The ePVR models were accurate to within 1.9 WU in over 75% of patients. In comparison to the ePASP, ePVR models performed similarly in terms of correlation, accuracy, and precision when estimating invasive hemodynamics. In screening for pulmonary hypertension, ePVR models had equivalent testing characteristics to the ePASP. Mid-systolic notching of the right ventricular outflow tract Doppler signal identified a subgroup of 11 patients (7%) with significantly elevated PVR and mean pulmonary artery pressures without relying on the acquisition of a tricuspid regurgitation signal. Analysis of ePVR and determination of the notching pattern of the right ventricular outflow tract Doppler flow velocity envelope provide reliable insights into hemodynamics in advanced lung disease patients, although limitations in precision exist.

Use of flecainide in combination antiarrhythmic therapy in patients with arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Antiarrhythmic therapy is commonly used for suppression of arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in conjunction with implantable cardioverter-defibrillators and catheter ablation. The efficacy of combination flecainide and sotalol/metoprolol therapy for patients refractory to single agents and/or catheter ablation has not been well established. OBJECTIVE: The purpose of this study was to describe our experience with the addition of flecainide in combination with sotalol/metoprolol for treatment of arrhythmias in patients with ARVC. METHODS: We reviewed all patients within our genetic arrhythmia program with a definite diagnosis of ARVC (45 patients) and identified 8 patients treated with a combination of flecainide with sotalol/metoprolol after failure of single-agent therapy and/or catheter ablation. These patients were monitored with at least yearly clinic visits and device interrogations focused on the detection of major ventricular arrhythmias. RESULTS: Of the 8 patients reviewed, 6 demonstrated excellent arrhythmia control after initiation of combination therapy with flecainide and sotalol/metoprolol. These patients have been arrhythmia-free for an average of 35.5 months. Two patients have demonstrated recurrent arrhythmias despite combination therapy and have undergone repeat epicardial and endocardial ablation. Recurrence was noted to occur within 2 months of therapy. Patients were diverse with regard to the severity of disease as well as in the presence of genetic mutations. CONCLUSION: The addition of flecainide in combination with sotalol/metoprolol may be an effective antiarrhythmic strategy for the control of ventricular arrhythmias in patients with ARVC refractory to single-agent therapy and/or catheter ablation.