This article is part of Pulmonology Advisor‘s coverage of the American Thoracic Society International Conference, taking place in Dallas, Texas. Our staff will report on medical research related to asthma and other respiratory conditions, conducted by experts in the field. Check back regularly for more news from ATS 2019.


DALLAS — The cardiopulmonary reserve index (CPRI) may be an effective predictor of survival in patients with pulmonary hypertension (PH), particularly in patients with PH caused by left heart disease (LHD), according to study findings presented at the American Thoracic Society International Conference held May 17-22, in Dallas, Texas.

“The [cardiovascular reserve index] has been proposed as an estimate of cardiovascular reserve based on stroke volume, systemic vascular resistance, respiratory rate, and body surface area in various conditions including heart failure and shock,” researchers wrote. Therefore, they sought to adapt the cardiovascular reserve index formula to pulmonary circulation to determine whether it could predict survival in patients with PH.

The researchers retrospectively obtained data from a total of 4363 patients who underwent a first diagnostic right heart catheterization between 1996 and 2006. A total of 1710 patients were diagnosed with PH; 125 cases of pulmonary arterial hypertension, 1410 cases of PH-LHD, 26 cases with PH caused by lung diseases and/or hypoxia, 105 cases with chronic thromboembolic PH, and 1 case with PH from unclear/multifactorial mechanisms. The following simplified formula was used to calculate CPRI: (20*mean pulmonary arterial pressure—mean pulmonary arterial wedge pressure)/(heart rate*body surface area).

In the overall PH group, CPRI was a predictor of survival according to the Cox regression analysis (hazard ratio [HR], 2.105; 95% CI, 1.319-3.360; P =.002). In a subgroup analysis stratified by PH groups, CPRI was only predictive of survival in patients with PH-LHD (HR, 4.370; 95% CI, 2.109-9.054; P <.001). The inclusion of pulmonary vascular resistance (HR, 1.017; 95% CI, 0.958-1.079; P =.587) in a multivariate Cox regression model demonstrated that CPRI was a persistent predictor of prognosis (HR, 3.640; 95% CI, 1.017-14.653; P =.046). Both CPRI (HR, 12.190; 95% CI, 4.310-34.478; P <.001) and diastolic pulmonary vascular pressure gradient (HR, 0.979; 95% CI, 0.936-0.995; P =.001) were considered multivariable predictors of PH-LHD prognosis.

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The researchers noted that further studies are needed to determine why CPRI is only a predictor of survival in PH-LHD and whether it could be helpful in guiding treatment.

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Reference

Shafran I, Gerges C, Gerges M, Segel M, Lang IM. Cardiopulmonary reserve index as predictor of survival in patients with pulmonary hypertension due to left heart disease. Presented at: the American Thoracic Society International Conference; May 22, 2019; Dallas, TX. Abstract A6794/P995.