Diastolic Pressure Difference to Classify Pulmonary Hypertension in the Assessment of Heart Transplant Candidates

Abstract

The DPD calculated in usual practice is underestimated in PH-LHD, which may classify Cpc-PH patients as isolated postcapillary pulmonary hypertension. The QRS-gated DPD reclassifies a subset of PH-LHD patients from isolated postcapillary pulmonary hypertension to Cpc-PH, which is characterized by an adverse hemodynamic profile.

Optimizing diastolic pressure gradient assessment

“…However, this approach suffers from an important inherent limitation, namely that it can only be employed in patients in sinus rhythm. In a recent investigation, instantaneous PAWP measurements at the onset of the QRS complex have been proposed for DPG calculation in order to attenuate the aforementioned methodological shortcomings of conventional DPG assessment [ 20 ]. This method, however, does not take into account the phase delay between the LAP and the PAWP, nor does it count with the electromechanical delay between depolarization and contraction.…”

“…An inherent major limitation of both of the aforementioned methods is that patients with atrial arrhythmias lack an A-wave and consequently a c-wave'; therefore, in a significant proportion of patients these measurements are not feasible. This limitation is overcome by the method, recently proposed by Wright and colleagues, namely to use the onset of the QRS complex to approximate the end diastolic PAWP [ 20 ]. This measurement is attainable in all patients; on the other hand, due to the time delay between the left atrial and PAW pressure together with the delay between depolarization and contraction, the suggested method will not actually capture end diastolic PAWP [ 21 ].…”

Significance of Pulmonary Vascular Resistance and Diastolic Pressure Gradient on the New Definition of Combined Post-Capillary Pulmonary Hypertension

“…18) Furthermore, it is known that DPG in usual practice is easily underestimated under conditions of elevated v wave of PAWP (e.g., mitral regurgitation). 19) Therefore, in such cases, the new criteria might be more useful and accurate than the 2015 ESC/ERS guidelines.…”

“…Conversely, Gerges, et al reported that the rate of Group B, which was unclassified as per the 2015 ESC/ ERS guidelines, was up to 30%, and they proposed defining Ipc-PH as PH-LHD with a DPG of < 7 mmHg and/or PVR of !3 WU, and Cpc-PH as PH-LHD with a DPG of "7 mmHg and PVR of > 3 WU. 6,20) The authors also demonstrated that DPG reflected pulmonary vascular remodeling, although the pulmonary artery samples they used were obtained from patients with extremely high DPG (> [15][16][17][18][19][20] and extremely elevated PVR, which is rare in LHD-PH. 6) Therefore, it cannot be said that DPG is an inappropriate factor for distinguishing between Ipc-PH and Cpc-PH only because DPG itself is not associated with prognosis.…”

Editor’s Perspective

“…The critical nature of accurate measurement of pulmonary hemodynamics and the importance of those measurements to HF, mechanical circulatory support, and transplant outcomes are explored in several original investigations, as well as expert commentary. [2][3][4][5] The science of pulmonary hypertension intersects in important ways with HF, particularly group 2 pulmonary hypertension, but also the importance of right ventricular function in all types of pulmonary hypertension, centering on coupling between the right ventricle and the pulmonary vasculature. In the coming year, you will see several such Spotlight issues, highlighting areas of growing scientific importance that are increasingly overlapping with the clinical areas of HF, mechanical circulatory support, and transplant.…”