Poor agreement between pulmonary capillary wedge pressure and left ventricular end-diastolic pressure in a veteran population.
BACKGROUND
Accurate determination of left ventricular filling pressure is essential for differentiation of pre-capillary pulmonary hypertension (PH) from pulmonary venous hypertension (PVH). Previous data suggest only a poor correlation between left ventricular end-diastolic pressure (LVEDP) and its commonly used surrogate, the pulmonary capillary wedge pressure (PCWP). However, no data exist on the diagnostic accuracy of PCWP in veterans. Furthermore, the effects of age and comorbidities on the PCWP-LVEDP relationship remain unknown.


METHODS
We investigated the PCWP-LVEDP relationship in 101 patients undergoing simultaneous right and left heart catherization at a large VA hospital. PCWP performance was evaluated using correlation and Bland-Altman analyses. Area under Receiver Operating Characteristics curves (AUROC) for PCWP were determined.


RESULTS
PCWP-LVEDP correlation was moderate (r = 0.57). PCWP-LVEDP calibration was poor (Bland-Altman limits of agreement -17.2 to 11.4 mmHg; mean bias -2.87 mmHg). 59 patients (58.4%) had pulmonary hypertension; 15 (25.4%) of those met pre-capillary PH criteria based on PCWP. However, if LVEDP was used instead of PCWP, 7/15 patients (46.6%) met criteria for PVH rather than pre-capillary PH. When restricting analysis to patients with a mean pulmonary artery pressure of ≥25 mmHg and pulmonary vascular resistance of >3 Wood units (n = 22), 10 patients (45.4%) were classified as pre-capillary PH based on PCWP ≤15 mmHg. However, if LVEDP was used, 4/10 patients (40%) were reclassified as PVH. Among patients with any type of pulmonary hypertension, PCWP discriminated moderately between high and normal LVEDP (AUROC, 0.81; 95%CI 0.69-0.94). PCWP-LVEDP correlation was particularly poor in patients with COPD or obesity.


CONCLUSIONS
Reliance on PCWP rather than LVEDP results in misclassification of veterans as having pre-capillary PH rather than PVH in almost 50% of cases. This is clinically relevant, as misclassification may lead to inappropriate therapies and adverse events.
Department of Medicine, Internal Medicine Residency Program, Krannert Institute of Cardiology, Indiana University, Indianapolis, Indiana, United States of America.
Abbas
A
Bitar
Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Krannert Institute of Cardiology, Indiana University, Indianapolis, Indiana, United States of America.
Mona
M
Selej
Department of Medicine, Krannert Institute of Cardiology, Indiana University, Indianapolis, Indiana, United States of America ; Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, United States of America.
Islam
I
Bolad
Department of Medicine, Division of Pulmonary, Allergy, Critical Care, Occupational and Sleep Medicine, Krannert Institute of Cardiology, Indiana University, Indianapolis, Indiana, United States of America ; Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, United States of America.
Tim
T
Lahm
D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D003937:Diagnosis, Differential; D004452:Echocardiography; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000503:physiopathology; D011667:Pulmonary Veins / Q000503:physiopathology; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D012372:ROC Curve; D012189:Retrospective Studies; D014655:Vascular Resistance / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*; D014728:Veterans / Q000706:statistics & numerical data*