Using Hemodynamic Marker Ratio to Predict Outcomes in Pulmonary Hypertension

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The ratio of hemodynamic markers from right heart catheterization can predict medication response in PH patients.
The ratio of hemodynamic markers from right heart catheterization can predict medication response in PH patients.

The ratio of hemodynamic markers derived from right heart catheterization can predict treatment outcomes in patients with pulmonary hypertension (PH). The retrospective analysis, published in Chest, examined the ratio of left to right ventricular end diastolic pressures (LVEDP/RVEDP) and its ability to predict disease severity and provide further insight into the interdependence between the ventricles.

Arun Jose, MD, from The George Washington University Medical Faculty Associates in Washington, DC, and colleagues sought to determine whether the LVEDP/RVEDP ratio could be used to predict response to pulmonary medications in patients with PH, the first study to do so.

The analysis was based on 51 adult patients who were treated with pulmonary vasodilators and had simultaneous right- and left-heart catheterization at Inova Fairfax Hospital in Falls Church, Virginia. The primary end point was the improvement in the 6-minute walk test (6MWT) of more than 35 meters per year with no hospitalization for worsening PH or additional therapy.

The patients were divided into 2 groups: responders (median age: 59±13.4; 95% women) and nonresponders (median age: 55.8±12.3, 73% women), based on their first clinically significant treatment event. There were 21 responders (41.2%) who had a mean improvement of 75 meters in the 6MWT. Nonresponders were patients whose 6MWT did not improve beyond 35 meters, were hospitalized, and needed additional PH medication.

The responders improved more quickly than the nonresponders (4.9 vs 6.4 months), had a higher RVEDP (14.1 vs 10.5; P =.047), a higher right atrial (RA) pressure (10.1 vs 7; P =.086), were more likely to be women (95% vs 73%; P =.064), and have a lower LVEDP/RVEDP ratio (1.08 vs 1.62; P =.051).

Even after adjusting for age, sex, severity of PH based on mean pulmonary air pressure (mPAP), pulmonary vascular resistance (PVR), RA pressure, and carbon monoxide (CO), the LVEDP/RVEDP ratio independently predicted a worse response to therapy (odds ratio [OR]: 0.22; 95% CI, 0.05-0.69; P =.025) as did a higher diastolic pulmonary gradient (DPG; OR: 0.87; 95% CI, 0.75-0.98; P =.033).

The highest levels of sensitivity and specificity were seen with a LVEDP/RVEDP ratio of ≤1.5, which had a sensitivity of 81% and a specificity of 50%.

The researchers also studied the effect of the LVEDP and RVEDP individually to predict treatment outcome, but neither was significant compared with the LVEDP/RVEDP ratio. Even the comparison between LVEDP and RVEDP was not significant (P =.785 and P =.184, respectively).

"In our study, the ventricular diastolic pressure ratio provided unique predictive information in determining which patients benefited from targeted PH therapy,” noted Dr Jose in an email interview with Pulmonology Advisor. “Currently, targeted therapy is not recommended in all patients with PH due to heart or lung disease, but has been shown to be beneficial in some. Our findings, if verified in future studies, may help clinicians decide how to effectively utilize targeted therapy in treating these types of patients.”

Study Limitations

  • The study population was from a single site
  • Patients were included in the study only if they had combined catheterizations
  • Though the disproportionate percentage of women in the study is common for PH trials, it was not possible to properly analyze for sex and therapeutic outcomes

Disclosures: Oksana A. Shlobin, MD, served as a consultant and is on the speakers' bureau for Actelion, Bayer, and United Therapeutics. Steven D. Nathan, MD, serves as a consultant and is on the speakers' bureau for and receives research funding from Bayer, Gilead, and United Therapeutics.

Reference

Jose A, King CS, Shlobin OA, et al. Ventricular diastolic pressure ratio as a marker of treatment response in pulmonary hypertension [published online May 17, 2017]. Chest. doi:10.1016/j.chest.2017.05.008  

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