Perfusion assessed by real-time contrast echocardiography correlates with clinical and echocardiographic parameters in patients with first STEMI treated with PCI - 6-month follow-up

Advances in Ultrasound Therapeutics

PURPOSE OF REVIEW

High mechanical index impulses from a diagnostic transducer are utilized in myocardial perfusion imaging, but can also be utilized therapeutically in three cardiovascular applications: (a) thrombus dissolution (sonothrombolysis), (b) improving microvascular flow in ischemic territories (sonoperfusion), and (c) targeted drug and nucleic acid delivery. The targeted therapeutic effect appears to be based on acoustic cavitation of the intravascular microbubbles which results in endothelial shear and pore formation, as well as mechanical destruction of thrombi.

RECENT FINDINGS

Within the last 5 years, clinical trials have been performed in acute myocardial infarction demonstrating successful reductions in myocardial infarct size with sonothrombolysis added to current guideline-based treatment. In patients with severe peripheral arterial disease, brief improvements in calf microvascular blood flow have been observed for 1 h after 10 min of sonoperfusion therapy. Targeted ultrasound therapies are developing for prevention of microvascular obstruction in acute coronary syndromes and peripheral vascular disease.

Event-Free Survival Following Successful Percutaneous Intervention in Acute Myocardial Infarction Depends on Microvascular Perfusion

Background:

Although small trials have detected microvascular obstruction (MVO) with variable frequency following restoration of epicardial blood flow, the independent impact of abnormal microvascular perfusion (MVP) in predicting patient outcome following emergent percutaneous coronary intervention in acute ST-segment–elevation myocardial infarction is unknown. The study aims to determine the impact of abnormal MVP following successful epicardial recanalization in ST-segment–elevation myocardial infarction.

Methods:

MVP was analyzed by low mechanical index ultrasound imaging within 48 hours of emergent percutaneous coronary intervention in 297 patients with acute ST-segment–elevation myocardial infarction who had restoration of Thrombolysis in Myocardial Infarction grade 3 flow in the infarct vessel. Patients were divided into normal segmental replenishment (normal MVP) after high mechanical index impulses versus delayed replenishment but normal plateau intensity (delayed MVP) and both delayed replenishment and reduced plateau intensity (MVO by definition). Demographic variables, left ventricular ejection fraction change, and 5-year follow-up of death, recurrent myocardial infarction, and congestive heart failure were analyzed.

Results:

MVO was seen in 115 patients (39%), delayed MVP in 124 (42%), and normal MVP in 58 patients (19%). Patients with MVO had significant lower left ventricular ejection fraction change (39±12%) at hospital discharge compared with delayed MVP (50±10%; P =0.003) and normal MVP (57±8%; P <0.0001) groups. The MVO group also did not have an improvement in left ventricular ejection fraction change at 3-month follow-up (36±12% versus 37±13%; P =0.18). Both delayed MVP and MVO were independent predictors of adverse events at follow-up (hazard ratio, 21 [CI, 4–116]; P =0.001 and hazard ratio, 30 [CI, 5–183]; P <0.0001, respectively).

Conclusions:

Reduced or absent MVP following successful percutaneous coronary intervention in acute ST-segment–elevation myocardial infarction is common and associated with significantly worse outcome even with Thrombolysis in Myocardial Infarction 3 flow in the infarct vessel.

Association between heart rate at rest and myocardial perfusion in patients with acute myocardial infarction undergoing cardiac rehabilitation - a pilot study

INTRODUCTION

This study was conducted to determine if there was a link among heart rate at rest (rHR), muscle volume changes, and single photon emission computed tomography (SPECT) parameters after 6-month cardiac rehabilitation in patients with acute myocardial infarction (AMI).

MATERIAL AND METHODS

Twenty-nine consecutive AMI patients (mean age: 63.0 ±9.1 years) who received appropriate percutaneous coronary intervention on admission were enrolled. (99m)Tc-Sestamibi myocardial SPECT images were obtained at the early (30 min) and delayed (4 h) phases after tracer injection at 2 weeks (0M) and 6 months (6M) after the onset of AMI. Within a few days of SPECT, all patients underwent cardiopulmonary exercise test for evaluation of cardiac rehabilitation effects. Before the initiation of exercise test, leg muscle volume was measured. All patients were stratified into the ≥ 70 beats per minute (bpm) (n = 15) or < 70 bpm (n = 14) group based on rHR at 6M.

RESULTS

There were no significant differences in the recanalization time, peak cardiac enzyme, or initial left ventricular ejection fraction between the two groups. After the 6-month training, the muscle volume changes in the lower limbs (< 70 bpm, 0.23 ±0.22; ≥ 70 bpm, -0.07 ±0.26, p < 0.05) were significantly greater in the < 70 bpm group than the ≥ 70 bpm group. The decreased rate of rHR had a significant correlation with the improved global severity (r = 0.62, p = 0.001) and extent (r = 0.48, p = 0.017) of left ventricle evaluated by (99m)Tc-Sestamibi myocardial SPECT delayed phase.

CONCLUSIONS

The result of this preliminary study demonstrated that improved myocardial perfusion was closely related to decreased rHR after cardiac rehabilitation.

Real-time myocardial contrast echocardiography as a useful tool to select candidates for coronary revascularization among patients with end-stage renal disease - a 3-year follow-up study

PURPOSE

To evaluate a real-time myocardial contrast echocardiography (MCE) as a tool to select candidates for coronary revascularization among patients with ESRD and to assess the rate of revascularization and mortality.

MATERIAL/METHODS

58 ESRD patients were screened for CAD using MCE. We analyzed the rate of coronary revascularization during 3-year follow-up. Patients with and without perfusion disturbances on MCE were compared.

RESULTS

CAD was found in 46.2% patients out of 39 who underwent coronary angiography. 11 (39.3%) patients out of 28 from the group with perfusion defects on MCE underwent revascularization procedure (21.4% - PCI, 17.9% - CABG). No one from the group without perfusion defects had revascularization procedure. Perfusion defect (OR 1.37 CI 1.37-1.86, p=0.022) was related to revascularization in multivariant analysis (OR 12.87, CI 1.86-89.21, p=0.025). There was no difference in mortality between the group which underwent invasive procedures and treated conservatively (p=0.6643). In ROC analysis defects on MCE and CAD on angiography were equally good in anticipating combined end-point (AUC 0.716, CI 95% 0.544-0.851 and AUC 0.747, CI 95% 0.577-0.875, p=0.701) and death (AUC 0.752, CI 95% 0.582-0.878 and AUC 0.729, CI 95% 0.558-0.861, p=0.805).

CONCLUSIONS

Our results indicate that MCE is a safe and uncomplicated method which may help along with other methods to select candidates for coronary revascularization among ESRD patients. In our study coronary revascularization procedures were successful but they did not improve patients' survival on 3-year follow-up.

Markers of kidney function in the elderly in relation to the new CKD-EPI formula for estimation of glomerular filtration rate

INTRODUCTION

Neutrophil gelatinase-associated lipocalin (NGAL) has been recently proved useful in the quantitation of chronic kidney disease (CKD). The aim of the study was to assess prevalence of CKD according to the Modification of Diet in Renal Disease (MDRD), Cockcroft-Gault, and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulae in 412 patients with normal serum creatinine and markers of kidney function/injury such as NGAL, cystatin C, and kidney injury molecule-1 (KIM-1) in these patients in relation to age (below and over 65 years).

MATERIAL AND METHODS

We included in the study 1005 patients with coronary artery disease and normal serum creatinine. However, markers of kidney function/injury were assessed in 412 patients. The NGAL, cystatin C and KIM-1, were assessed using commercially available kits.

RESULTS

Patients over 65 years had significantly lower estimated glomerular filtration rate (eGFR) than their younger counterparts despite identical creatinine. They also had significantly lower haematocrit, despite similar Hb, lower platelet count, higher serum fibrinogen, higher systolic (SBP) and lower diastolic blood pressure, higher serum NGAL and cystatin C, but similar urinary NGAL and KIM-1. Serum NGAL correlated with age, haematocrit, leukocyte, platelet and erythrocyte count, eGFR, creatinine, fasting glucose, HbA(1c), fibrinogen, SBP, and diabetes duration. In multiple regression analysis kidney function (eGFR, creatinine clearance or creatinine), cystatin C and SBP were predictors of serum NGAL.

CONCLUSIONS

In our study we found a very high prevalence of CKD up to 61% in elderly patients with coronary artery disease and normal serum creatinine. Neutrophil gelatinase-associated lipocalin could be a sensitive marker of kidney function, particularly in elderly patients with another risk factor for kidney damage, i.e. hypertension.