Impact of hypertension on infarct size in ST elevation myocardial infarction patients undergoing primary angioplasty

Hypertension, microvascular obstruction and infarct size in patients with STEMI undergoing PCI: Pooled analysis from 7 cardiac magnetic resonance imaging studies

BACKGROUND

Mortality after ST-segment elevation myocardial infarction (STEMI) is increased in patients with hypertension. The mechanisms underlying this association are uncertain. We sought to investigate whether patients with STEMI and prior hypertension have greater microvascular obstruction (MVO) and infarct size (IS) compared with those without hypertension.

METHODS

We pooled individual patient data from 7 randomized trials of patients with STEMI undergoing primary percutaneous coronary intervention (PCI) in whom cardiac magnetic resonance imaging was performed within 1 month after reperfusion. The associations between hypertension and MVO, IS, and mortality were assessed in multivariable adjusted models.

RESULTS

Among 2174 patients (61.3 ± 12.6 years, 76% male), 1196 (55.0%) had hypertension. Patients with hypertension were older, more frequently diabetic and had more extensive coronary artery disease than those without hypertension. MVO and IS measured as percent LV mass were not significantly different in patients with and without hypertension (adjusted differences 0.1, 95% CI -0.3 to 0.6, P = .61 and -0.2, 95% CI -1.5 to 1.2, P = .80, respectively). Hypertension was associated with a higher unadjusted risk of 1-year death (hazard ratio [HR] 2.28, 95% CI 1.44-3.60, P < .001), but was not independently associated with higher mortality after multivariable adjustment (adjusted HR 1.04, 95% CI 0.60-1.79, P = .90).

CONCLUSION

In this large-scale individual patient data pooled analysis, hypertension was not associated with larger IS or MVO after primary PCI for STEMI.

Hypertension and patients with acute coronary syndrome: Putting blood pressure levels into perspective

Arterial hypertension is a well-established cardiovascular risk factor, and blood pressure (BP) control has largely improved the prognosis of hypertensive patients. A number of studies have assessed the role of BP levels in the prognosis of patients with acute coronary syndromes. Pathophysiologic links of hypertension to acute myocardial infarction (MI) include endothelial dysfunction, autonomic nervous system dysregulation, impaired vasoreactivity, and a genetic substrate. A history of hypertension is highly prevalent among patients presenting with MI, and some, but not all, studies have associated it with a worse prognosis. Some data support that low levels of admission and in-hospital BP may indicate an increased risk for subsequent events. Risk scores used in patients with MI have, therefore, included BP levels and a history of hypertension in their variables. Of note, good long-term BP control, ideally initiated prior to discharge, should be pursued in order to improve secondary prevention.

Hypertension, Microvascular Pathology, and Prognosis After an Acute Myocardial Infarction

The rationale for our study was to investigate the pathophysiology of microvascular injury in patients with acute ST-segment-elevation myocardial infarction in relation to a history of hypertension. We undertook a cohort study using invasive and noninvasive measures of microvascular injury, cardiac magnetic resonance imaging at 2 days and 6 months, and assessed health outcomes in the longer term. Three hundred twenty-four patients with acute myocardial infarction (mean age, 59 [12] years; blood pressure, 135 [25] / 79 [14] mm Hg; 237 [73%] male, 105 [32%] with antecedent hypertension) were prospectively enrolled during emergency percutaneous coronary intervention. Compared with patients without antecedent hypertension, patients with hypertension were older (63 [12] years versus 57 [11] years; P<0.001) and a lower proportion were cigarette smokers (52 [50%] versus 144 [66%]; P=0.007). Coronary blood flow, microvascular resistance within the culprit artery, infarct pathologies, inflammation (C-reactive protein and interleukin-6) were not associated with hypertension. Compared with patients without antecedent hypertension, patients with hypertension had less improvement in left ventricular ejection fraction at 6 months from baseline (5.3 [8.2]% versus 7.4 [7.6]%; P=0.040). Antecedent hypertension was a multivariable associate of incident myocardial hemorrhage 2-day post-MI (1.81 [0.98-3.34]; P=0.059) and all-cause death or heart failure (n=47 events, n=24 with hypertension; 2.53 [1.28-4.98]; P=0.007) postdischarge (median follow-up 4 years). Severe progressive microvascular injury is implicated in the pathophysiology and prognosis of patients with a history of hypertension and acute myocardial infarction. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT02072850.

Antecedent hypertension and myocardial injury in patients with reperfused ST-elevation myocardial infarction

BACKGROUND

Antecedent hypertension is associated with poor outcome in patients with ST-elevation myocardial infarction (STEMI). Whether differences in myocardial salvage, infarct size and microvascular injury contribute to the adverse outcome is unknown. We investigated the association between antecedent hypertension and cardiovascular magnetic resonance (CMR) parameters of myocardial salvage and damage in a multicenter CMR substudy of the AIDA-STEMI trial (Abciximab Intracoronary versus intravenously Drug Application in ST-elevation myocardial infarction).

METHODS

We analyzed 792 consecutive STEMI patients reperfused within 12 h after symptom onset. Patients underwent CMR imaging for assessment of myocardial salvage, infarct size and microvascular obstruction within 10 days after infarction. Major adverse cardiac events (MACE) were recorded at 12-month follow-up.

RESULTS

Antecedent hypertension was present in 540 patients (68 %) and was associated with a significantly increased baseline risk profile (advanced age, higher body mass index, higher incidence of diabetes, hypercholesterolemia, previous angioplasty and multivessel disease, p < 0.001 for all). MACE were more frequent in patients with hypertension as compared to patients without hypertension (45 [8 %] vs. 8 [3 %], p < 0.01). Antecedent hypertension remained an independent predictor of MACE after multivariate adjustment (hazard ratio 3.42 [confidence interval 1.45-8.08], p < 0.01). There was, however, no significant difference in the area at risk, infarct size, myocardial salvage index, extent of microvascular obstruction, and left ventricular ejection fraction between the groups (all p > 0.05).

CONCLUSION

Despite a higher rate of MACE in contemporary reperfused STEMI patients with antecedent hypertension, there was no difference in reperfusion efficacy, infarct size and reperfusion injury as visualized by CMR.

TRIAL REGISTRATION

NCT00712101 .

Clinical characteristics and short-term outcomes in patients with elevated admission systolic blood pressure after acute ST-elevation myocardial infarction: a population-based study

OBJECTIVE

Prognostic value of lower admission systolic blood pressure (SBP) in patients with acute myocardial infarction has been confirmed, but the impact of elevated admission SBP on short-term outcomes has been evaluated only by a limited number of studies and they have reported conflicting results. The aim of our study was to investigate the characteristics and short-term outcomes in patients with elevated admission SBP after ST-elevation myocardial infarction (STEMI).

DESIGN

A population-based, observational study.

SETTING

The multicentre registry in China.

PARTICIPANTS

A total of 7510 consecutive patients with STEMI were registered. Patients were divided into three groups according to admission SBP: normal admission SBP (100-139 mm Hg), modestly elevated admission SBP (140-179 mm Hg) and excessively elevated admission SBP (≥180 mm Hg). The primary outcomes were 7-day and 30-day all-cause mortality, major adverse cardiac events (MACE) and bleeding rate.

RESULTS

Of 6591 patients, 4182 (63.5%) had normal admission SBP, 2187 (33.2%) modestly elevated admission SBP and 222 (3.4%) excessively elevated admission SBP. Patients with elevated admission SBP had a high-risk profile, such as were more likely to be older, with more concomitant cardiovascular morbidities, presenting with more events of anterior myocardial infarction and less reperfusion treatment. However, 7-day and 30-day all-cause mortality, MACE and bleeding rate were comparable among groups (all p>0.05). Survival curves and MACE curves were similar among groups (p=0.377 and 0.375, respectively). After multivariate adjustment, elevated admission SBP was not associated with increased risk of short-term death and bleeding, and MACE was comparable with normal admission SBP.

CONCLUSIONS

Although those with elevated admission SBP after STEMI were at a higher risk for cardiovascular events, they did not have poorer short-term outcomes compared with patients with normal admission SBP.