Unravelling the Difference Between Men and Women in Post-CABG Survival

Objectives

Women have a worse prognosis after coronary artery bypass grafting (CABG) surgery compared to men. We sought to quantify to what extent this difference in post-CABG survival could be attributed to sex itself, or whether this was mediated by difference between men and women at the time of intervention. Additionally, we explored to what extent these effects were homogenous across patient subgroups.

Methods

Time to all-cause mortality was available for 102,263 CABG patients, including 20,988 (21%) women, sourced through an individual participant data meta-analysis of five cohort studies. Difference between men and women in survival duration was assessed using Kaplan-Meier estimates, and Cox's proportional hazards model.

Results

During a median follow-up of 5 years, 13,598 (13%) patients died, with women more likely to die than men: female HR 1.20 (95%CI 1.16; 1.25). We found that differences in patient characteristics at the time of CABG procedure mediated this sex effect, and accounting for these resulted in a neutral female HR 0.98 (95%CI 0.94; 1.02). Next we performed a priori defined subgroup analyses of the five most prominent mediators: age, creatinine, peripheral vascular disease, type 2 diabetes, and heart failure. We found that women without peripheral vascular disease (PVD) or women aged 70+, survived longer than men (interaction p-values 0.04 and 6 × 10-5, respectively), with an effect reversal in younger women.

Conclusion

Sex differences in post-CABG survival were readily explained by difference in patient characteristics and comorbidities. Pre-planned analyses revealed patient subgroups (aged 70+, or without PVD) of women that survived longer than men, and a subgroup of younger women with comparatively poorer survival.

Carotid Intima-Media Thickness Progression as Surrogate Marker for Cardiovascular Risk: Meta-Analysis of 119 Clinical Trials Involving 100 667 Patients

BACKGROUND

To quantify the association between effects of interventions on carotid intima-media thickness (cIMT) progression and their effects on cardiovascular disease (CVD) risk.

METHODS

We systematically collated data from randomized, controlled trials. cIMT was assessed as the mean value at the common-carotid-artery; if unavailable, the maximum value at the common-carotid-artery or other cIMT measures were used. The primary outcome was a combined CVD end point defined as myocardial infarction, stroke, revascularization procedures, or fatal CVD. We estimated intervention effects on cIMT progression and incident CVD for each trial, before relating the 2 using a Bayesian meta-regression approach.

RESULTS

We analyzed data of 119 randomized, controlled trials involving 100 667 patients (mean age 62 years, 42% female). Over an average follow-up of 3.7 years, 12 038 patients developed the combined CVD end point. Across all interventions, each 10 μm/y reduction of cIMT progression resulted in a relative risk for CVD of 0.91 (95% Credible Interval, 0.87-0.94), with an additional relative risk for CVD of 0.92 (0.87-0.97) being achieved independent of cIMT progression. Taken together, we estimated that interventions reducing cIMT progression by 10, 20, 30, or 40 μm/y would yield relative risks of 0.84 (0.75-0.93), 0.76 (0.67-0.85), 0.69 (0.59-0.79), or 0.63 (0.52-0.74), respectively. Results were similar when grouping trials by type of intervention, time of conduct, time to ultrasound follow-up, availability of individual-participant data, primary versus secondary prevention trials, type of cIMT measurement, and proportion of female patients.

CONCLUSIONS

The extent of intervention effects on cIMT progression predicted the degree of CVD risk reduction. This provides a missing link supporting the usefulness of cIMT progression as a surrogate marker for CVD risk in clinical trials.

Progression of conventional cardiovascular risk factors and vascular disease risk in individuals: insights from the PROG-IMT consortium

AIMS

Averaged measurements, but not the progression based on multiple assessments of carotid intima-media thickness, (cIMT) are predictive of cardiovascular disease (CVD) events in individuals. Whether this is true for conventional risk factors is unclear.

METHODS AND RESULTS

An individual participant meta-analysis was used to associate the annualised progression of systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol with future cardiovascular disease risk in 13 prospective cohort studies of the PROG-IMT collaboration (n = 34,072). Follow-up data included information on a combined cardiovascular disease endpoint of myocardial infarction, stroke, or vascular death. In secondary analyses, annualised progression was replaced with average. Log hazard ratios per standard deviation difference were pooled across studies by a random effects meta-analysis. In primary analysis, the annualised progression of total cholesterol was marginally related to a higher cardiovascular disease risk (hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.00 to 1.07). The annualised progression of systolic blood pressure, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol was not associated with future cardiovascular disease risk. In secondary analysis, average systolic blood pressure (HR 1.20 95% CI 1.11 to 1.29) and low-density lipoprotein cholesterol (HR 1.09, 95% CI 1.02 to 1.16) were related to a greater, while high-density lipoprotein cholesterol (HR 0.92, 95% CI 0.88 to 0.97) was related to a lower risk of future cardiovascular disease events.

CONCLUSION

Averaged measurements of systolic blood pressure, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol displayed significant linear relationships with the risk of future cardiovascular disease events. However, there was no clear association between the annualised progression of these conventional risk factors in individuals with the risk of future clinical endpoints.

The gender-specific role of polymorphisms from the fibrinolytic, renin-angiotensin, and bradykinin systems in determining plasma t-PA and PAI-1 levels

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) directly influence thrombus formation and degradation and thus risk for arterial thrombosis. We report here results from a genetic analysis of plasma t-PA and PAI-1 levels in a large population-based sample from the PREVEND study in Groningen, the Netherlands (n=2,527). We measured polymorphisms from genes of the fibrinolytic system, the reninangiotensin system (RAS), and the bradykinin system. We found that males had higher levels of natural-log transformed t-PA, and PAI-1 (P < 0.01) compared to females. When stratifying females by menopausal status, PAI-1 levels were only significantly different between pre-menopausal females and males (p<0.001). Furthermore, we found that age, body mass index, and waist-to-hip ratio were significant predictors of t-PA and PAI-1 in both females and males, and that the regression relationships between these factors and plasma t-PA and PAI-1 were dependent on gender. In addition, we found that the PAI-1 4G/5G polymorphism was a significant predictor of PAI-1 levels in both females and males, that the angiotensin II type I receptor A1166C wasa significant predictor of t-PA and PAI-1 levels in females, and that the bradykinin receptor B2 58CT polymorphism was a significant predictor of t-PA levels in females. In conclusion, this large population-based study showed that t-PA and PAI-1 levels are determined by several demographic and genetic factors involved in the fibrinolytic, RAS and bradykinin system. In addition, the results support the idea that the biology of t-PA and PAI-1 is different between females and males.

Left ventricular assessment in myocardial infarction: the VALIANT registry

BACKGROUND

How often echocardiography and cardiac catheterization are used to evaluate left ventricular (LV) function in patients with myocardial infarction (MI) and how they are associated with quality of care is unknown.

METHODS

Patients with MI in the Valsartan in Acute Myocardial Infarction (VALIANT) registry were divided into those with (n = 1423) and without (n = 3968) heart failure (HF), and the use of either echocardiography or cardiac catheterization for LV assessment in each group was compared along with associated baseline characteristics. We evaluated the association between LV assessment and discharge medications. Using a multivariable model with a propensity analysis, we evaluated the association of LV assessment with in-hospital outcomes.

RESULTS

Of the patients with HF, 322 (22.6%) had no LV assessment. Patients with HF with LV assessment were discharged more frequently under treatment with aspirin (81.3% vs 70.0%; P<.001), beta-blockers (65.6% vs 56.4%; P = .008), clopidogrel (30.4% vs 14.0%; P<.001), and statins (45.9% vs 34.2%; P<.001). Patients without HF who underwent LV assessment were discharged more frequently under treatment with an angiotensin-converting enzyme inhibitor (53.8% vs 41.5%; P<.001). After adjustment for regional use, other covariates, and revascularization, LV assessment was associated with lower in-hospital mortality in patients with HF (adjusted odds ratio [OR], 0.45; P<.001) and in patients without HF (adjusted OR, 0.30; P<.001). After excluding deaths during the first 2 days, LV assessment remained associated with lower mortality in patients with HF (adjusted OR, 0.59; P = .03) and in patients without HF (adjusted OR, 0.41; P<.001).

CONCLUSION

Left ventricular assessment was frequently not performed during the in-hospital stay of patients with acute MI, including those with clinical HF, and its use was associated with better quality of care.

An international perspective on heart failure and left ventricular systolic dysfunction complicating myocardial infarction: the VALIANT registry

AIMS

We analysed the contemporary incidence, outcomes, and predictors of heart failure (HF) and/or left ventricular systolic dysfunction (LVSD) before discharge in patients with acute myocardial infarction (MI). The baseline presence of HF or LVSD, or its development during hospitalisation, increases short- and long-term risk after MI, yet its incidence, predictors, and outcomes have not been well described in a large, international, general MI population.

METHODS AND RESULTS

The VALIANT registry included 5573 consecutive MI patients at 84 hospitals in nine countries from 1999 to 2001. A multivariable logistic survival model was constructed using baseline variables to determine the adjusted mortality risk for those with in-hospital HF and/or LVSD. Baseline variables were also tested for associations with in-hospital HF and/or LVSD. Of the 5566 patients analysed, 42% had HF and/or LVSD during hospitalisation. Their in-hospital mortality rate was 13.0% compared with 2.3% for those without HF and/or without LVSD. After adjustment for other baseline risk factors, in-hospital HF and/or LVSD carried a hazard ratio for in-hospital mortality of 4.12 (95% confidence interval: 3.08-5.56). Patients with HF and/or LVSD also had disproportionately higher rates of other cardiovascular events.

CONCLUSIONS

HF and/or LVSD is common in the general contemporary MI population and precedes 80.3% of all in-hospital deaths after MI. Survivors of early MI-associated HF and/or LVSD have more complications, longer hospitalisations, and are more likely to die during hospitalisation. Although baseline variables can identify MI patients at highest risk for HF and/or LVSD, such patients are less likely to receive indicated procedures and medical therapies.