Haemodynamically Derived Pulmonary Artery Pulsatility Index Predicts Mortality in Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary artery (PA) pulsitility index (PAPi) is a novel haemodynamic index shown to predict right ventricular failure in acute inferior myocardial infarction and post left ventricular assist device surgery. We hypothesised that PAPi calculated as [PA systolic pressure - PA diastolic pressure]/right atrial pressure (RAP) would be associated with mortality in the National Institutes of Health Registry for Primary Pulmonary Hypertension (NIH-RPPH). METHODS: The impact of PAPi, the Pulmonary Hypertension Connection (PHC) risk score, right ventricular stroke work, pulmonary artery capacitance (PAC), other haemodynamic indices, and demographic characteristics was evaluated in 272 NIH-RPPH patients using multivariable Cox proportional hazards (CPH) regression and receiver operating characteristic (ROC) analysis. RESULTS: In the 272 patients (median age 37.7+/-15.9years, 63% female), the median PAPi was 5.8 (IQR 3.7-9.2). During 5years of follow-up, 51.8% of the patients died. Survival was markedly lower (32.8% during the first 3years) in PAPi quartile 1 compared with the remaining patients (58.5% over 3years in quartiles 2-4; p<0.0001). The best multivariable CPH survival model included PAPi, the PHC-Risk score, PAC, and body mass index (BMI). In this model, the adjusted hazard ratio for death with increasing PAPi was 0.946 (95% CI 0.905-0.989). The independent ROC areas for 5-year survival based on bivariable logistic regression for PAPi, BMI, PHC Risk, and PAC were 0.63, 0.62, 0.64, and 0.65, respectively (p<0.01). The ROC area for 5-year survival for the multivariable logistic model with all four covariates was 0.77 (p<0.0001). CONCLUSIONS: Pulmonary artery pulsatility index was independently associated with survival in PAH, highlighting the utility of PAPi in combination with other key measures for risk stratification in this population.

Increased Pulmonary-Systemic Pulse Pressure Ratio Is Associated With Increased Mortality in Group 1 Pulmonary Hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterised by remodelling of the pulmonary vasculature leading to right ventricular (RV) failure. The failing RV, through interventricular uncoupling, deleteriously impacts the left ventricle and overall cardiac efficiency. We hypothesised that the ratio of the pulmonary artery pulse pressure to the systemic pulse pressure ("pulmonary-systemic pulse pressure ratio", or PS-PPR) would be associated with mortality in PAH. METHODS: We conducted a retrospective analysis of 262 patients in the National Institute of Health Primary Pulmonary Hypertension Registry (NIH-PPH). We evaluated the association between the PS-PPR and mortality after adjustment for the Pulmonary Hypertension Connection (PHC) risk equation. RESULTS: Among 262 patients (mean age 37.5±15.8years, 62.2% female), median PS-PPR was 1.04 (IQR 0.79-1.30). In the Cox proportional hazards regression model, each one unit increase in the PS-PPR was associated with more than a two-fold increase in mortality during follow-up (HR 2.06, 95% CI 1.40-3.02, p=0.0002), and this association of PS-PPR with mortality remained significant in the multivariable Cox model adjusted for the PHC risk equation, mean pulmonary artery pressure, and body mass index (BMI) (adjusted HR 1.81, 95% CI 1.13-2.88, p=0.01). Furthermore, PS-PPR in the upper quartile (>1.30) versus quartiles 1-3 was associated with a 68% increase in mortality after adjustment for these same covariates (adjusted HR 1.68, 95% CI 1.13-2.50, p=0.01). CONCLUSIONS: Pulmonary-systemic pulse pressure ratio, a marker of biventricular efficiency, is associated with survival in PAH even after adjustment for the PHC risk equation. Further studies are needed on the wider applications of PS-PPR in PAH patients.

6-Minute walk test predicts prolonged hospitalization in patients undergoing transcatheter mitral valve repair by MitraClip.

BACKGROUND: The 6-minute walk test (6MWT) is a simple functional test that can predict exercise capacity and is widely employed to assess treatment outcomes. Although mortality with transcatheter mitral valve repair (TMVr) using the MitraClip (Abbott Vascular, Menlo Park, CA) is significantly less than for open mitral valve surgery in high-risk patients, identifying which patient will benefit the most from TMVr remains a concern. There are limited prognostic metrics guiding patient selection and, no studies have reported relationship between prolonged hospitalization and 6MWT. This study aimed to determine if the 6MWT can predict prolonged hospitalization in patients undergoing TMVr by MitraClip. METHODS: We retrospectively reviewed 162 patients undergoing 6MWT before TMVr. Patients were divided into three groups according to the 6MWT distance (6MWTD) using the median (6MWTD ≥219 m, 6MWTD <219 m, and Unable to Walk). Multivariate logistic regression model was applied to select the demographic characteristics that were associated with the prolonged hospitalization defined as total length of stay ≥4 days in the study. RESULTS: We found that 6MWT (odds ratio 3.64, 95% confidence interval 2.03-6.52, P < 0.001) was independently associated with prolonged hospitalization after adjustment in multivariate analysis. Area under the curve of 6MWT for predicting prolonged hospitalization was 0.79 (95% confidence interval 0.72-0.85). CONCLUSIONS: Our study demonstrates that 6MWT was independently associated with prolonged hospitalization in patients with TMVr, and has a good discriminatory performance for predicting prolonged hospitalization.

Impending paradoxical embolism presenting as a pulmonary embolism, transient ischemic attack, and myocardial infarction.

A 25-year-old man presented with complaints of nonpleuritic, substernal chest pain, dyspnea, and decreasing exercise tolerance. His vital signs were normal, with the exception of an oxygen saturation level of 93% while breathing room air. During his assessment, he developed transient left facial droop, left arm and leg weakness, and an ataxic gait, which lasted 15 min then resolved spontaneously. Cardiac enzyme levels were elevated, and an ECG revealed T-wave inversion in leads III, aVF, V1, and V2 with evolving ST-segment elevation in leads V3 through V5. The findings of a CT scan and MRI of the head were negative; a Doppler ultrasound of the right lower extremity revealed a thrombus extending from the common femoral vein to the popliteal vein. Cardiac catheterization revealed no evidence of epicardial coronary artery disease. CT pulmonary angiography revealed bilateral pulmonary emboli. Transesophageal echocardiography (TEE) showed a 4-cm, dumbbell-shaped mass lodged in a patent foramen ovale, confirming the diagnosis of an impending paradoxical embolism. The patient was started on therapy with unfractionated heparin, and his thrombus resolved spontaneously by hospital day 5. An impending paradoxical embolism is rare but should be suspected in anyone presenting with evidence of both venous and arterial emboli. The therapeutic options include anticoagulation, thrombolysis, and surgical embolectomy. We would propose that initial treatment with anticoagulation therapy and following with serial TEEs may be appropriate therapy in an otherwise stable patient, with surgical embolectomy or thrombolysis reserved for the treatment of thrombi that do not resolve with anticoagulation therapy or for patients with clinical deterioration.

Cardioprotection by multiple preconditioning cycles does not require mitochondrial K(ATP) channels in pigs.

To test whether cardioprotection induced by ischemic preconditioning depends on the opening of mitochondrial ATP-sensitive K(+) (K(ATP)) channels, the effect of channel blockade was studied in barbital-anesthetized open-chest pigs subjected to 30 min of complete occlusion of the left anterior descending coronary artery and 3 h of reflow. Preconditioning was elicited by two cycles of 5-min occlusion plus 10-min reperfusion before the 30-min occlusion period. 5-Hydroxydecanoate (5 mg/kg iv) was injected 15 min before preconditioning or pharmacological preconditioning induced by diazoxide (3.5 mg/kg, 1 ml/min iv). Infarct size (percentage of the area at risk) after 30 min of ischemia was 35.1 +/- 9.9% (n = 7). Preconditioning markedly limited myocardial infarct size (2.7 +/- 1.6%, n = 7), and 5-hydroxydecanoate did not abolish protection (2.4 +/- 0.9%, n = 8). Diazoxide infusion also significantly limited infarct size (14.6 +/- 7.4%, n = 7), and 5-hydroxydecanoate blocked this effect (30.8 +/- 8.0%, n = 7). Thus the opening of mitochondrial K(ATP) channels is cardioprotective in pigs, but these data do not support the hypothesis that opening of mitochondrial K(ATP) channels is required for the endogenous protection afforded by preconditioning.