Value of reserve pulse pressure in improving the risk stratification of patients with normal myocardial perfusion imaging.
AIMS
To evaluate the incremental prognostic value of reserve-pulse pressure (reserve-PP: exercise-PP minus rest-PP) to standard risk factors among patients with suspected coronary artery disease (CAD) but normal exercise myocardial perfusion imaging (MPI).


METHODS AND RESULTS
We studied 4269 consecutive symptomatic patients without known CAD who were referred for exercise MPI but had normal MPI results (mean age 58 ± 12 years, 56% females, 84% referred for evaluation of chest pain or dyspnoea, 95% with intermediate pretest likelihood of CAD). There were 202 deaths over 5.1 ± 1.4 years of follow-up. Reserve-PP was abnormal (<44 mmHg increase in PP from rest) in 1894 patients (44%). Patients with an abnormal reserve-PP had a higher risk of death compared with patients with normal reserve-PP [hazard ratio (HR): 2.47, 95% CI, 1.8-3.3]. In multivariable models adjusting for age, sex, ejection fraction, medications, heart rate recovery, Duke treadmill score (DTS), and rest-PP, each 10 mmHg lower reserve-PP was associated with a 20.6% increase in risk-adjusted mortality (adjusted HR 0.83, 95% CI 0.76-0.91). Models incorporating reserve-PP significantly reclassified risk compared with models without these parameters (net reclassification index 14.3%, P = 0.0007; integrated discrimination index 0.69, P = 0.01).


CONCLUSION
In patients without a history of CAD and a normal MPI, an abnormal reserve-PP identified and reclassified those at higher risk of death independent of known risk factors and DTS.