Peak Circulatory Power : a new parameter of cardiopulmonary exercise testing to predict arrhythmic events in patients with implantable cardioverter defibrillator for primary prevention Rita Calé, Miguel Mendes, António Ferreira, João Brito, Pedro Sousa, Pedro Carmo, Francisco Costa, Pedro Adragão, João Calqueiro, José Aniceto Silva. H o s p i t a l d e S a n t a C r u z C H L O Lisbon, Portugal
Cause of Death in Heart Failure European Heart Journal (2008);29:2388-2442
ICDs: the only therapeutic with clearly benefit in sudden cardiac death prevention
ICD implant rate over Europe for million habitant
Ejection Fraction has been used to identify patients that could benefit from ICD implantation Myerburg RJ et al. New Engl J Med 2008;359:2245-53
n Background Aim Methods Results Limitations of the Ejection Fraction as a criteria to ICD No Sudden Death Sudden Death LV Ejection Fraction FN FP Exner D et al. Curr Opin Cardiol 2009;24:61-67
Patient selection for prophylactic implantable cardioversordefibrillator (ICD) therapy in primary prevention of sudden cardiac death must be improved to decrease the rate of useless implantations. Cardiopulmonary exercise testing (CPET) is a powerful technique in prognosis stratification of dilated cardiomyopathy, however no data are known about the ability of this test to predict malignant arrhythmic events in ICD patients.
Cardiopulmonary exercise testing (CPET) is widely used to assess disease severity and prognosis in patients with Chronic Heart Failure Lee Ingle, Heart Fail Ver 2007; 12:12-22 Gitt A, Wasserman K, Kilkowsky C, Circulation 2002; 106:3079-3084
Eur Heart J 2002;23:806-814
Eur Heart J 2002;23:806-814
To assess the value of CPET variables, including the new parameter of peak circulatory power, as predictors of malignant arrhythmic events in ICD patients for primary prevention of sudden cardiac death.
Single centre registry; 71 consecutive patients with dilated cardiomyopathy and an ICD implanted for primary prevention of sudden cardiac death. Inclusion period: 2003-2009 Inclusion Criteria CPET 6 months before the ICD implantation NYHA class II-IV Exclusion criteria Age < 18 years ICD follow-up in other institution Clinical follow-up < 4 months
Cardiopulmonary exercise testing Ergometer: treadmill; Exercise protocol: investigator s choice; Parameters: Peak VO2; VE/VCO2 slope; peak circulatory power; rest heart rate, chronotropic reserve and delta systolic blood pressure (difference between peak and rest). Combined end-point mortality due to arrhythmic death,ventricular fibrillation (VF), or sustained ventricular tachycardia (SVT), whatever occurred first.
Follow-up Conducted by clinical records and phone interview Arrhythmic events detected by ICD and confirmed by electrograms analysis Statistical analysis Univariate and multivariate Hazard Ratios (HR) - Cox proportional hazards Discriminating power - ROC curve analysis
- Clinical Basic Characteristics Demographic Male, n (%) 55 (78) Age, mean±sd 56 ± 12 Cardiovascular risk factors Diabetes Mellitus, n (%) 18 (25) Hypertension, n (%) 31 (44) Dyslipidemia, n (%) 39 (55) Smoking habits, n (%) 44 (62) BMI, average±sd 27 ± 4 Past cardiovascular history AMI, n (%) 35 (49) PCI, n (%) 19 (27) CABG, n (%) 12 (17) Medications N=71 B-blocker, n (%) 60 (84) ACE inhibitor, AT2 blocker, n (%) 69 (97) Diuretics 56 (79) Amiodarone 18 (25) Digoxin 19 (27) Miocardiopathy etiology Ischemic, n (%) 36 (51) LV ejection fraction 31±9
- Cardiopulmonary exercise testing Protocols Ramp, n (%) 34 (48) Naughton, n (%) 28 (39) Modified Bruce, n (%) 6 (9) Bruce, n (%) 3 (4) Maximal test RER 1,10, n (%) 62 (87) Exercise variables, mean±sd Peak VO2, ml.kg -1.min -1 16.6±4.5 VE/VCO2 slope 37.3±10.2 % predicted VO2 max 57.2±17.6 Anaerobic threshold, ml.kg -1.min -1 12.4±3.1 Peak circulatory power, mmhgml/kg/min 2327.6±944.1 N=71
Arrhythmic events and Death (%) Background Aim Methods Results - Follow-up: 672 ± 470 days (median 497 days) Arrhythmic events in patients with implantable cardioverter-defibrillator for primary prevention 40 35 30 23 pts, 32% 25 pts, 35% 25 20 15 10 5 7 pts, 10% 2 pts, 3% 9 pts, 13% 0 All causes Death Arrhythmic Death VF VT Combined endpoint
Clinical Variables Arrhythmic Event (+) Arrhythmic Event (-) p N=25 N=46 Age, mean±sd 56.9±10.1 52.3±13.4 0.595 Male, n (%) 18 (72.0) 37 (80.4) 0.553 Diabetes Mellitus, n (%) 10 (40.0) 8 (17.4) 0.048 Hypertension, n (%) 11 (44.0) 20 (43.5) 1.000 Dyslipidemia, n (%) 13 (52.0) 26 (56.5) 0.805 Smoking habits, n (%) 17 (68.0) 27 (58.7) 0.459 BMI, average±sd 28.5±4.5 26.6±3.8 0.073 Ischemic myocardiopathy, n (%) 13 (52.0) 23 (50.0) 1.000 Beta-blocker, n (%) 17 (68.0) 43 (93.5) 0.007 Amiodarone, n (%) 7 (28.0) 11 (23.9) 0.778 Digoxin, n (%) 10 (40.0) 9 (19.6) 0.092 ACE inhibitor, AT2 blocker, n (%) 25 (100.0) 44 (95.7) 0.537 Diuretics, n (%) 23 (92.0) 33 (71.7) 0.067
- Hazard Ratio of Arrhythmic death/vf/vt (Univariate analysis) CPET variables, mean (SD) HR CI (95%) p Peak VO2 0.870 0.791-0.958 0.004 % predicted VO2 max 0.975 0.952-0.999 0.041 Anaerobic threshold 0.802 0.682-0.942 0.007 VE/VCO2 slope 1.035 0.998-1.073 0.061 Rest heart rate 1.031 1.001-1.062 0.040 Chronotropic reserve 0.990 0.973-1.007 0.228 Δ HR decrease on recovery 1st min 0.984 0.959-1.010 0.218 Peak systolic BP 0.983 0.967-0.999 0.035 Δ Systolic BP 0.974 0.954-0.994 0.013 Peak circulatory power* 0.924 0.876-0.975 0.004 * For each 100 units
- Adjusted Hazard Ratio of Arrhythmic death/vf/vt (Multivariate analysis) Multivariate analysis adjusted for age, ischemic myocardiopathy and beta-blockers
Sensibilidade Sensitivity Background Aim Methods Results Predictive Accuracy of Peak Circulatory Power to Arrhythmic events Peak Circulatory Power na Profilaxia Primária 100 80 PCP 2350 mmhg.ml/kg/min 60 40 20 0 p=0,001 0 20 40 60 80 100 100-Especificidade 100-Specificity (AUC 0.70; 95% CI, 0.58-0.81) Sensitivity 80% Specificity 56% PPV 50% NPV 84%
Arrhythmic death/vf/vt Background Aim Methods Results Log Rank p =0,002 Days The best cut-off in our population was a value of PCP 23,5 mmhg.ml/kg/min/100 (AUC 0,70; 95%CI 0,58-0,81) with negative predictive value of 84%.
Peak circulatory power was the only independent predictor for malignant arrhythmic events in this population of DCM patients and primary prevention ICD.
Cardiopulmonary exercise test can contribute to improve patient s selection for prophylactic ICD.