Summary
Background
The association between admission pulse pressure (PP) and cardiovascular outcomes in acute coronary syndrome (ACS) is not well defined.
Aim
To explore the prognostic value of initial PP in ST-segment elevation myocardial infarction (STEMI) and non-ST elevation ACS (NSTE-ACS).
Methods
Over a 5-month period in 2007, 6704 consecutive patients with ACS were categorized into five groups according to initial PP: P1, PP ≤ 0; P2, PP 31–40; P3, PP 41–50; P4, PP 51–60; P5, PP > 60 mmHg. Patient characteristics and in-hospital outcomes were analysed.
Results
Mean PP was lower in men versus women (55 ± 19 vs. 61 ± 22), young versus old (53 ± 17 vs. 59 ± 21), STEMI vs. NSTE-ACS (51 ± 18 vs. 60 ± 18) and patients who died versus survived (46 ± 22 vs. 57 ± 19 mmHg) ( P < 0.001 for all). Most patients with low PP had a high Global Registry of Acute Coronary Events risk score. Compared with P5, crude odds ratios (ORs) (95% confidence intervals) for death were: P1, 9 (5.78–13.35); P2, 3 (1.71–4.06); P3, 1.5 (1.01–2.49); P4, 0.90 (0.51–1.58). After adjustment, low PP was associated with high mortality and stroke rates in ACS (adjusted ORs 7.5 [3.77–14.72] and 4.5 [1.20–18.88], respectively), high rates of recurrent ischaemia in NSTE-ACS (adjusted OR 2.8 [1.52–5.22]) and a high heart failure rate in STEMI (adjusted OR 2.1 [1.18–3.76]). Women with low PP had a higher mortality rate than men .
Conclusion
In ACS, all blood pressure variables were significantly correlated. Low PP was an independent predictor for stroke and mortality in overall ACS. Although PP was not superior to systolic blood pressure, only low PP was an independent predictor for recurrent ischaemia in NSTE-ACS.
Résumé
Justification
L’association entre la pression pulsée à l’admission et les évènements cardiovasculaires au décours d’un syndrome coronaire aigu n’est pas bien connue.
Objectifs
Évaluer l’impact pronostique de la pression pulsée à l’admission chez des patients ayant un syndrome coronaire aigu avec (STEMI) ou sans sus décalage du segment ST (NSTE-ACS).
Méthode
Pendant une durée de cinq mois, 6704 patients consécutifs ayant un syndrome coronaire aigu ont été répartis en groupes en fonction de la pression pulsée à l’admission : P1 pression pulsée ≤ 30, P2 PP 31–40, P3 PP 51–60, P5 PP > 60 mmHg. Les caractéristiques de base de ces patients et les évènements cardiovasculaires en phase hospitalière ont été analysés.
Résultats
La pression pulsée moyenne était significativement moindre chez les hommes comparativement aux femmes (59 ± 19 vs. 61 ± 22 mmHg), chez les patients jeunes comparativement aux sujets âgés (53 ± 17 vs. 59 ± 21 mmHg), en cas de STEMI versus NSTE-ACS (51 ± 18 versus 60 ± 18 mmHg) et chez les patients décédés comparativement aux survivants (46 ± 22 vs. 57 ± 19 mmHg) ( p < 0,001 pour l’ensemble de ces variables). La majorité des patients ayant une pression pulsée basse avaient un score GRACE élevé. Comparativement au groupe P5, l’odd ratio non ajusté (ORs) (IC 95 %) était le suivant pour les décès P1, 9 (IC 95 %, 5,78–13,35) ; P2, 3 (IC 95 %, 1,71–4,06) ; P3, 1,5 (IC 95 %, 1,01–2,49) ; P4 0,90 IC 95 %, (0,51–1,58). Après ajustement, la pression pulsée est associée à une surmortalité de risque accru (ORs 7,5, IC 95 % 3,77–14,72) et à un taux accru d’AVC 4,5 (1,20–18,88), avec un taux plus élevé de récidive d’ischémie dans le syndrome coronaire aigu sans sus décalage du ST, NSTE-ACS (OR ajusté 2,8 [IC 95 %, 1,52–5,22]) et un taux accru d’insuffisance cardiaque chez les patients ayant un STEMI (odd ratio 2,1 [IC 95 %, 1,18–3,76]). Les femmes ayant une pression pulsée moindre avaient un taux de mortalité augmenté comparativement aux autres.
Conclusion
Dans le syndrome coronaire aigu, toutes les variables dérivées de la pression artérielles sont significativement corrélées. Une pression pulsée basse est un prédicteur indépendant du risque d’AVC et de surmortalité quel que soit leur type de syndrome coronaire aigu. Bien que la pression pulsée ne soit pas supérieure à la pression artérielle systolique, seule une pression pulsée basse est un prédicteur indépendant de la récidive ischémique dans les syndromes coronaires aigus sans sus décalage de ST.
Background
Arterial blood pressure (BP) variables that are easily obtainable at the bedside include systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP) and pulse pressure (PP). Although these BP variables are of clinical importance in many cardiovascular disorders, the best predictor to consider in clinical practice is not well defined . PP arises as a consequence of the episodic nature of cardiac contraction and the properties of the arterial circulation; it reflects stiffness of the aorta and large arteries, and pulse wave velocity . Recently, PP has been identified as a more powerful prognostic predictor of cardiovascular events than SBP and DBP in selected populations . Data from the population-based Framingham Heart Study showed that neither SBP nor DBP was superior to high PP in predicting coronary heart disease risk in middle-aged and elderly patients . However, most of these findings were extracted from studies that evaluated the impact of PP in non-acute cardiovascular situations. Therefore, data on the prognostic influence of the initial hospital recording of the pulsatile components of the arterial BP wave (i.e. PP) in acute coronary events is lacking. The only available reports on PP after acute myocardial infarction (MI) were provided for a particular subgroup of high-risk patients, namely those with impaired left ventricular function . The present study explores data from the Gulf Registry of Acute Coronary Events (Gulf RACE) to assess whether low versus high PP measured on admission plays an additional prognostic role in patients presenting with ST-segment elevation MI (STEMI) and non-ST elevation acute coronary syndrome (NSTE-ACS).
Methods
The data are derived from a prospective, multicentre, observational study of the Gulf RACE. In 2007 and for 5 months, the Gulf RACE investigators recruited 6704 consecutive acute coronary syndrome (ACS) patients from 64 hospitals in six Middle Eastern countries (Bahrain, Kuwait, Qatar, Oman, United Arab Emirates and Yemen). The study received ethical approval from the institutional ethical bodies in all participating countries. The rationale and details of the Gulf RACE have been described previously . All participating centres were committed by written consent to include every consecutive patient with ACS. All patients gave informed consent to participate and care was taken to ensure data anonymity. Data were collected on record forms by the treating physicians. Completed data sheets were sent to the central data processing centre for uniform monitoring and registration. The primary outcome was in-hospital mortality rate. The secondary outcomes included recurrent myocardial ischaemia, heart failure (HF) and stroke.
Brachial PP was used as a marker of the pulsatile component of BP. A single BP measurement was taken with a sphygmomanometer at the time of presentation in the supine position; PP was calculated as the difference between SBP and DBP; MAP was calculated as two-thirds DBP plus one-third SBP. To explore the relationship between in-hospital outcome and arterial pressure indices, BP values were analysed as continuous and categorical variables. In the latter case, BP values were grouped in 10-mmHg classes according to the following cut-off values: P1, ≤ 30; P2, 31–40; P3, 41–50; P4, 51–60; P5, > 60 mmHg .
Briefly, diagnosis of the different types of ACS and definitions of data variables were based on the American College of Cardiology clinical data standard . For the purpose of this report, ST-segment elevation MI and left bundle branch block MI were grouped together and called STEMI; non-ST-segment elevation MI and unstable angina were grouped together and called NSTE-ACS. An attempt was made to include everyone with a final diagnosis of ACS and there were no exclusion criteria .
Statistical analysis
Data are presented as proportions, medians or means ± standard deviations (SDs) as appropriate. Differences in categorical variables between respective comparison groups were analysed using the chi-square test. The continuous variables were analysed using one-way analysis of variance. The multivariable model for the predictors of the in-hospital outcomes included the following potential covariates: age, sex, diabetes mellitus, hypertension, ejection fraction, troponin T, aspirin, clopidogrel, glycoprotein inhibitors, beta-blockers and angiotensin-converting enzyme inhibitors. To assess the linear relationship among some or all of the independent variables in the regression model, collinearity was tested by calculating the correlation coefficient among the BP variables. Owing to collinearity between BP variables, only PP and SBP variables were taken into the multivariable analysis. All p values were two-sided tailed. P values < 0.05 were considered significant. In a subanalysis, PP patients were divided into two groups (≤ 30 vs. > 30 mmHg) for comparing the mortality rate in each group, stratified by the admission Killip class. All data analyses were carried out using the Statistical Package for Social Sciences, version 14 (SPSS Inc., Cary, NC, USA).
Results
Among 6704 patients who presented with ACS, data were successfully completed for 6638 patients. The mean PP, SBP, DBP and MAP were 56.5 ± 20, 139.8 ± 31, 83.5 ± 18 and 102 ± 20, respectively. Mean PP was lower in men compared with in women (55 ± 19 vs. 61 ± 22, P < 0.001) and in younger age compared with older age (53 ± 17 vs. 59 ± 21, P < 0.001). Table 1 describes patients’ characteristics in different PP subgroups. Among all PP groups, cardiovascular risk factors were less frequent in patients presenting with initial low PP, except for smoking and renal impairment. Patients with low PP were characterized by a higher resting heart rate and higher Killip class on admission. In comparison with high PP, patients in the P1 group presented far more frequently with STEMI (56% vs. 27%, P = 0.001), a higher level of peak troponin T (23 ± 61 vs. 14 ± 53, P = 0.005) and a left ventricular ejection fraction < 40% (36% vs. 19%, P = 0.001). Patients in the P1 group were less likely to receive evidence-based medications and were less likely to undergo coronary angiography.
| PP ≤ 30 | PP 31–40 | PP 41–50 | PP 51–60 | PP > 60 | P | |
|---|---|---|---|---|---|---|
| Number (%) | 533 (8) | 1244 (19) | 1550 (23) | 1241 (19) | 2070 (31) | |
| Demographics | ||||||
| Age | 57 ± 14 | 54 ± 12 | 54 ± 12 | 56 ± 12 | 59 ± 12 | 0.001 |
| Women (%) | 24.0 | 18.8 | 20.4 | 22.8 | 31.7 | 0.001 |
| Medical history | ||||||
| Diabetes (%) | 35.6 | 32.9 | 36.5 | 40.8 | 50.8 | 0.001 |
| Hypertension (%) | 38.6 | 36.5 | 41.8 | 50.3 | 67.7 | 0.001 |
| Dyslipidaemia (%) | 23.8 | 26.2 | 30.4 | 32.4 | 38.7 | 0.004 |
| Smokers (%) | 41.5 | 44.9 | 41.5 | 39.1 | 29.8 | 0.001 |
| Renal impairment (%) | 26.9 | 16.9 | 14.9 | 14.0 | 20.3 | 0.001 |
| Prior CAD (%) | 46.7 | 40.3 | 43.5 | 45.7 | 50.6 | 0.001 |
| Clinical characteristics | ||||||
| Peak troponin (ng/mL) | 23 ± 61 | 21 ± 52 | 16 ± 45 | 16 ± 48 | 14 ± 53 | 0.005 |
| Heart rate | 88 ± 31 | 84 ± 23 | 85 ± 22 | 86 ± 22 | 87 ± 22 | 0.002 |
| Systolic BP | 97 ± 23 | 118 ± 17 | 131 ± 15 | 143 ± 19 | 169 ± 26 | 0.001 |
| Diastolic BP | 72 ± 22 | 79 ± 16 | 82 ± 15 | 86 ± 17 | 89 ± 20 | 0.001 |
| MAP | 81 ± 21 | 92 ± 16 | 99 ± 16 | 105 ± 19 | 117 ± 21 | 0.001 |
| Body mass index | 27 ± 5 | 27 ± 5 | 27 ± 5 | 28 ± 5 | 28 ± 6 | 0.009 |
| Symptoms > 12 hours (%) | 47.5 | 34.2 | 29.3 | 25.8 | 25.0 | 0.001 |
| Killip > class 1 (%) | 33 | 20 | 17 | 18 | 27 | 0.001 |
| No typical angina (%) | 23.1 | 17.2 | 16.7 | 19.5 | 24.0 | 0.001 |
| LVEF < 40% (%) | 36.3 | 24.3 | 20.8 | 21.7 | 19.3 | 0.001 |
| Discharge diagnosis | ||||||
| NSTE-ACS (%) | 44.2 | 48.6 | 59.8 | 63.3 | 72.8 | 0.001 |
| STEMI (%) | 55.8 | 51.4 | 40.2 | 36.7 | 27.2 | 0.001 |
| Hospital treatments | ||||||
| Aspirin (%) | 97.1 | 97.5 | 98.3 | 98.2 | 98.1 | 0.32 |
| Clopidogrel (%) | 48.3 | 55.0 | 56.4 | 53.9 | 52.6 | 0.01 |
| GP IIb/IIIa inhibitor (%) | 5.9 | 9.2 | 12.1 | 10.2 | 11.5 | 0.001 |
| Beta-blockers (%) | 48.1 | 62.2 | 69.4 | 68.9 | 66.5 | 0.001 |
| Statins (%) | 73.8 | 77.2 | 82.8 | 81.7 | 83.8 | 0.001 |
| Heparin (%) | 91.9 | 93.2 | 93.7 | 93.8 | 91.5 | 0.05 |
| ACE inhibitors (%) | 53.8 | 66.1 | 67.3 | 70.3 | 75.7 | 0.001 |
| Coronary angiogram (%) | 13.3 | 16.1 | 19.4 | 19.5 | 20.6 | 0.001 |
| Hospital outcomes | ||||||
| Recurrent ischaemia (%) | 11.6 | 11.2 | 8.1 | 8.3 | 8.0 | 0.002 |
| Heart failure (%) | 25.9 | 17.2 | 12.1 | 15.4 | 16.9 | 0.001 |
| Cardiogenic shock (%) | 20.9 | 6.6 | 3.2 | 2.4 | 2.6 | 0.001 |
| Stroke (%) | 2.2 | 0.6 | 0.4 | 0.5 | 0.8 | 0.001 |
| Mortality (%) | 14.7 | 4.5 | 2.7 | 1.7 | 1.7 | 0.001 |
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