Relation of Pulmonary Artery Pressure and Renal Impairment in ST Segment Elevation Myocardial Infarction Patients

Association between central venous pressure as assessed by echocardiography, left ventricular function and acute cardio-renal syndrome in patients with ST segment elevation myocardial infarction

BACKGROUND

Recent reports have demonstrated the adverse effects of venous congestion on renal function in patients with heart failure. None of these trials, however, has evaluated the effect of acute myocardial ischemia on the occurrence of acute kidney injury (AKI).

METHODS

We conducted a retrospective study of 1336 ST segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) between June 2012 and June 2016. Comprehensive echocardiographic examination was performed within 72 h of hospital admission. Non-invasive evaluation of central venous pressure (CVP) was estimated from measurements of inferior vena cava diameter and its collapsibility. Intermediate-high CVP was defined as ≥ 8 mm/Hg. Patients were stratified according to left ventricular ejection fraction (LVEF) and CVP and assessed for AKI.

RESULTS

Intermediate-high CVP was associated with AKI both in patients with LVEF greater than 45% and those with 45% or lower. Patients having LVEF ≤ 45% and intermediate-high CVP had a 10-fold increase in the incidence of AKI compared to patients with LVEF > 45% and normal CVP (39 vs. 4%). In a multivariable logistic regression model, intermediate-high CVP was independently associated with AKI (OR = 2.73, 95% CI 1.54-4.87; p = 0.001). Other variables associated with AKI included LVEF ≤ 45% (OR = 2.37, 95%CI 1.25-4.51; p = 0.008), time to reperfusion, mechanical ventilation and chronic kidney disease.

CONCLUSIONS

Among STEMI patients undergoing PCI, the utilization of simple echocardiographic measurements (LVEF and CVP) may be useful for early identification of those at high risk for AKI.

Acute kidney injury is associated with microvascular myocardial damage following myocardial infarction

Acute kidney injury (AKI) is a frequent complication in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention. However, the pathophysiology of AKI in this setting is complex and goes beyond the administration of contrast media. Studies assessing the impact of infarct characteristics on AKI are currently lacking. Therefore, we investigated the association of AKI with myocardial as well as microvascular injury in an initial total of 361 consecutive STEMI patients treated by primary percutaneous coronary intervention. Of these, 318 patients were included in final analysis. Serum creatinine was measured on admission as well as 24, 48, and 72 hours thereafter with AKI defined as an increase in serum creatinine of 0.3 mg/dl or more. Cardiac magnetic resonance (CMR) scans were performed in the first week after infarction, with microvascular injury visualized by late gadolinium enhancement CMR defined as any region of hypoenhancement within the hyperenhanced area of infarction. Sixteen patients developed AKI. They showed significantly lower left ventricular ejection fraction (45[interquartile range 40-52]% vs. 54[47-59]%), larger infarct size (21[15-35]% vs. 12[7-22]%) of left ventricular myocardial mass, and more frequent microvascular injury (81 vs. 46%) than those free of AKI. Meaningfully, in multivariate analysis including all CMR data, microvascular injury was the sole independent predictor of AKI (odds ratio 6.74, 95% confidence interval of 1.49-30.43). Thus, among revascularized STEMI patients, the presence of microvascular injury assessed by CMR was independently associated with an increased risk of AKI. This suggests a potential pathophysiological link between cardiac microvascular disease and renal injury following STEMI.