PH still tied to poor prognosis in adults with heart valve disease
Analysis took into account new guidelines for what defines pulmonary hypertension
Among patients undergoing surgery for a heart valve disease, the presence of pulmonary hypertension (PH) was associated with a worse prognosis, particularly for patients with high pulmonary vascular resistance (PVR).
PVR is an an indicator of resistance to blood flow in the pulmonary arteries sending blood from the heart to the lungs and is a core feature of precapillary PH subtypes, including pulmonary arterial hypertension (PAH).
This recent analysis was performed taking into account last year’s changes in the European Society of Cardiology/European Respiratory Society (ECS/ERS) guidelines for what defines PH and its subtypes.
With the new criteria, more patients were being classified as having PH than with the earlier thresholds.
The study, “Updated definition of pulmonary hypertension and outcome after transcatheter aortic valve implantation,” was published in Heart.
PH is defined as an increase in mean pulmonary artery pressure (mPAP) — the pressure in the vessels sending blood from the heart to the lungs. It can be further subdivided based on other measurements, one of which is PVR.
While elevated PVR is associated with precapillary PH, such an elevation is not seen in postcapillary PH, where the pulmonary veins sending blood from the lungs back to the heart also are affected due to left-sided heart disease. In some cases, patients may have a combination of these types.
In the recent update, ECS/ERS guidelines shifted the recommendations for what mPAP values constitute a PH diagnosis. The threshold was lowered from 25 millimeters of mercury (mm Hg, a pressure unit) to 20 mm Hg under the new guidelines. Cutoff for PVR also was lowered.
Aortic stenosis is a relatively common heart disease in older people where the heart’s valve narrows and blood can’t flow normally. For people who undergo surgery to correct this, the presence of PH is known to negatively affect their prognosis.
But that was according to the old cutoff criteria for PH. Until now, it wasn’t known whether a similar relationship would be observed with the new criteria.
Transcatheter aortic valve implantation (TAVI) surgery
In their study, the scientists examined data from 579 patients, with a median age of 82, who underwent a surgery called transcatheter aortic valve implantation (TAVI) for aortic stenosis at a center in Italy.
The proportion of these patients considered to have PH increased under the new definition, from 32% with the old criteria to 52% with the new.
Proportions of PH subtypes also were altered, with the proportion of patients having precapillary or combined PH rising from 11.1% to 31.6%, and the proportion of those with postcapillary PH declining from 28.9% to 20%.
This shift was partly due to 64 people previously identified as having postcapillary PH being reclassified as having precapillary/combined disease.
Patients with PH more often had chronic obstructive pulmonary disease, a chronic lung disease, or atrial fibrillation, a chaotic and irregular heartbeat, compared to those without PH.
Over a median follow-up of 2.9 years after surgery, PH according to the old criteria was associated with worse survival and a higher risk of hospitalization for heart failure, regardless of PH subtype.
According to the new cutoffs, PH also was linked to worse outcomes, particularly among patients who had high PVR, or those with precapillary or combined PH.
A month after surgery, pulmonary artery pressure normalized for 45% of patients according to the newer thresholds. Pressure normalization was  associated with survival benefits only in patients with post-capillary disease.
“The current study is the first and the largest analysis exploring at long-term follow-up (up to 7 years) of the prognostic role of the new versus old ESC/ERS PH classification in patients treated by TAVI,” the researchers wrote.
Taken together, the researchers believe the findings indicate that right heart catheterization, an invasive procedure that can evaluate mPAP and PVR, should be performed in patients deemed likely to have PH.
“When high PH probability was found at preprocedural non-invasive diagnostic tests, invasive right heart catheterisation may be considered to provide relevant prognostic information on postprocedural outcomes,” the scientists wrote.
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