Management of cardiogenic shock complicating acute myocardial infarction: towards evidence based medical practice

The Cardiac Power Index during Abdominal Open Aortic Surgery: Intraoperative Insights into the Cardiac Performance-A Retrospective Observational Analysis

Background: The Cardiac Power Index (CPI) measures the rate of energy output generated by the heart and correlates this with in-hospital mortality due to cardiogenic shock. In open aortic surgery, both aortic clamping and unclamping expose the heart to abrupt variations of the left ventricle afterload, preload, and contractility, with possible hemodynamic impairment. We investigated how aortic-cross clamping (Ao-XC) and unclamping (Ao-UC) procedures affect the CPI during open aortic surgery. Methods: We retrospectively analyzed our surgical database of 67 patients submitted to open surgical aortic repair at Humanitas Research Hospital, Milan. Patients were monitored by an EV1000-FloTrac SystemTM (Edwards Lifescience, Irvine, CA, USA) beyond the standard intra-operative hemodynamic monitoring. The primary outcome was the variation of basal CPI after aortic clamping and unclamping. Secondary outcomes were variations of the cardiac index (CI), mean arterial pressure (MAP), heart rate, and lactate during aortic clamping and after unclamping. The CPI was computed as: (CI × MAP)/451. Results: The CPI changed significantly after aortic unclamping. CPI: basal = 0.39 ± 0.1 W/m2, after Ao-XC = 0.39 ± 0.1 W/m2, and after Ao-UC = 0.44 ± 0.2 W/m2, p < 0.05. The CI changed during both cross-clamping and unclamping (p < 0.0001), whilst the MAP and heart rate did not during any phase of the surgery. Five subjects (8.3%) needed inotropic support after cross-clamping. Their basal CPI was lower than the general population: 0.31 ± 0.11 W/m2 vs. 0.39 ± 0.1 W/m2. Conclusions: The CPI describes the adaptation of the cardiac function to the changes in preload, contractility, and afterload occurring during aortic cross-clamping and unclamping. It may be used to explore the cardiac performance in real-time and predict cardiac impairment in the intraoperative period in a minimally invasive way, similar to ventriculo-arterial coupling parameters.

Use of Levosimendan in Intensive Care Unit Settings: An Opinion Paper

Levosimendan is an inodilator that promotes cardiac contractility primarily through calcium sensitization of cardiac troponin C and vasodilatation via opening of adenosine triphosphate–sensitive potassium (K_ATP) channels in vascular smooth muscle cells; the drug also exerts organ-protective effects through a similar effect on mitochondrial K_ATP channels. This pharmacological profile identifies levosimendan as a drug that may have applications in a wide range of critical illness situations encountered in intensive care unit medicine: hemodynamic support in cardiogenic or septic shock; weaning from mechanical ventilation or from extracorporeal membrane oxygenation; and in the context of cardiorenal syndrome. This review, authored by experts from 9 European countries (Austria, Belgium, Czech republic, Finland, France, Germany, Italy, Sweden, and Switzerland), examines the clinical and experimental data for levosimendan in these situations and concludes that, in most instances, the evidence is encouraging, which is not the case with other cardioactive and vasoactive drugs routinely used in the intensive care unit. The size of the available studies is, however, limited and the data are in need of verification in larger controlled trials. Some proposals are offered for the aims and designs of these additional studies.

Early revascularization is beneficial across all ages and a wide spectrum of cardiogenic shock severity: A pooled analysis of trials

BACKGROUND

A pooled analysis in cardiogenic shock due to acute coronary syndromes is desirable to assess the effect of early revascularization (ERV) across all ages and a wide spectrum of disease severity.

METHODS

Only two randomized controlled trials (RCT), i.e. SMASH and SHOCK, met the inclusion criteria and were combined for a pooled analysis using individual patient data (n = 348).

RESULTS

SMASH patients (n = 54, 16%) had more severe disease than SHOCK patients (n = 294, 84%). After adjustment for age, anoxic brain damage, non-inferior myocardial infarction, prior coronary artery bypass graft surgery, renal failure, systolic blood pressure, and selection for coronary angiography, one-year mortality was similar (relative risk SHOCK versus SMASH 0.87, 95% CI: 0.61-1.25). Relative risk of one-year death for ERV versus initial medical stabilization was 0.82 (95% CI: 0.70-0.96). There was no significant difference in the treatment effect by age (≤75 years relative risk at one year 0.79, 95% CI: 0.63-0.99; > 75 years relative risk at one year 0.93, 95% CI: 0.56-1.53; interaction P = 0.10).

CONCLUSIONS

Only two RCT have been published emphasizing the difficulty of enrolling critically ill patients. Despite large differences in shock severity, ERV benefit is similar across all ages and not significantly different for the elderly.

Cardiogenic shock after primary percutaneous coronary intervention: Effects of levosimendan compared with dobutamine on haemodynamics

BACKGROUND

Levosimendan is a new calcium sensitizer with positive inotropic properties. Cardiac power output (CPO) has been shown to be instrumental in the diagnosis of cardiogenic shock (CS) and is an important determinant of outcomes.

AIMS

To evaluate the haemodynamic effects of levosimendan compared to dobutamine in acute myocardial infarction (AMI) patients revascularised by primary percutaneous coronary intervention (PCI), who developed CS.

METHODS AND RESULTS

Twenty two consecutive AMI patients revascularised by PCI, who developed CS, were randomly assigned to levosimendan (24 microg kg(-1) bolus plus 24-h continuous infusion 0,1 microg kg(-1) min(-1)) or dobutamine (initial dose 5 microg kg(-1) min(-1), with a maximum dose adjustment in order to reach the desired haemodynamic effect). Evaluations were performed from baseline to 30 h. The primary end-point was an increase > or =30% in CPO, after 24 h of therapy. The baseline clinical and haemodynamic characteristics were similar in both groups. Levosimendan had a consistently better effect on CPO than dobutamine, while the decrease in PCWP was similar.

CONCLUSION

The primary objective of our study was achieved better by the end of the 24 h infusion of levosimendan than by dobutamine.

Myocardial perfusion grade and survival after percutaneous transluminal coronary angioplasty in patients with cardiogenic shock

We sought to evaluate myocardial reperfusion and its prognostic value after percutaneous transluminal coronary angioplasty (PTCA) in patients admitted for cardiogenic shock. Lack of myocardial reperfusion despite restored coronary flow affects the survival of patients with acute myocardial infarction (AMI). Myocardial blush grade (MBG) is an angiographic measure of myocardial perfusion. We assessed MBG in 41 consecutive patients admitted to our department within 12 hours from the onset of AMI and in cardiogenic shock. PTCA was successful in 83% of patients. Thrombolysis In Mycardial Infarction (TIMI) grade 3 flow was demonstrated in 22 patients (53%). MBG 2/3 was found in 14 patients (34%); among them, 12 had TIMI 3 flow. Compared with patients with MBG 2/3, those with MBG 0/1 were older (71 +/- 11 vs 57 +/- 13 years, p = 0.001), had a higher prevalence of diabetes (48% vs 14%, p = 0.04) and hypertension (63% vs 29%, p = 0.04), showed a trend toward longer ischemic time (6.1 +/- 2.4 vs 4.9 +/- 1.1), and had larger enzymatic infarct size (peak creatine kinase 7,690 +/- 3,516 vs 5,500 +/- 2,977 IU/L). Mortality was higher in patients with MBG 0/1 both in the hospital (81% vs 14%, p <0.001) and at follow-up (81% vs 29%, p = 0.001). After adjustment by multivariate analysis, MBG 0/1 (odds ratio 16, p = 0.01) and age (odds ratio 3.8/10 years, p = 0.04) were correlated with in-hospital mortality. MBG 2/3 was achieved in a few patients in cardiogenic shock after AMI who were treated with PTCA; this was a strong predictor of in-hospital survival. Also, risk stratification after mechanical revascularization should include assessment of restoration of myocardial reperfusion.

Pressure response to vasopressors and mortality after direct angioplasty for cardiogenic shock

BACKGROUND

There is very little known about the relationship between pre-intervention arterial pressure response to vasopressor therapy (PRV) and death rate, after primary angioplasty for immediate cardiogenic shock (CS) complicating acute myocardial infarction (AMI).

METHODS

We examined data from 32 consecutive cases, admitted to our department within 12 h after the onset of MI and in CS, treated with direct PTCA, from May 1995 to March 2001. Intravenous administration of dobutamine and vasopressor agents was required in all patients before intervention.

RESULTS

Ten patients, after vasopressor therapy, showed a significant improvement in systolic arterial pressure, invasively measured, (>90 mmHg, responders) before undergoing PTCA. Responders were younger and with less impaired pre-procedural LVEF (39.6%+/-10.7 vs. 30.9%+/-8.4, P=0.02). After direct PTCA responders showed an improved final TIMI flow (2.8+/-0.6 vs. 2.2+/-0.7, P=0.04) and blush grade (1.9+/-0.9 vs. 1+/-1, P=0.03). The mortality rate was lower in responders compared with non-responders both in hospital (20% vs. 68%, P=0.02) and at 3.5 years of follow-up (30% vs. 73%, P=0.049). After adjustment by multivariate analysis older age and lower blush grade correlated with in hospital death, while age remained the only predictor of late death.

CONCLUSIONS

PRV was not an independent predictor of death after direct PTCA for CS. The association of no PRV with older age and lower post procedural blush grade may explain the difference in mortality rates between responders and non-responders.

Survival of patients treated with intra-aortic balloon counterpulsation for cardiogenic shock in a tertiary centre: variables correlated with death

OBJECTIVE

To describe the characteristics and mortality rates of 132 cardiogenic shock patients treated with intra-aortic balloon counterpulsation at a university hospital.

INTERVENTIONS

All patients underwent intra-aortic balloon counterpulsation. A total of 99 out of 132 patients were revascularized with angioplasty, surgery or were transplanted (intervention group), 33 out of 132 had no further intervention (no-intervention group).

MEASUREMENTS AND RESULTS

Overall mortality was 54.5% (72/132). In the intervention group mortality was 50.5% (50/99), in the no-intervention group mortality was 66.6% (22/33). The odds ratio for death comparing the intervention group with the no-intervention group was 0.533 (95% confidence interval 0.238-1.189, P = 0.122). By univariate analysis, diabetes and a left ventricular ejection fraction of less than 0.35 represented an increased odds ratio of death of 4.25 (1.813-9.965, P = 0.001) and 3.03 (1.22-7.54, P = 0.015), respectively. A lactate level greater than 2.5 mg/dl at baseline resulted in an increased odds ratio of death of 5.185 (1.988-13.525, P = 0.0001). Using a multivariate logistic regression analysis, a left ventricular ejection fraction less than 0.35 and diabetes remained significantly correlated with death.

CONCLUSION

Mortality rates remain high in cardiogenic shock patients in need of intra-aortic balloon counterpulsation. The odds ratio for death tended to be lower in the intervention group compared with the no-intervention group, although the absolute difference in mortality as a result of an intervention was only 15.2%, and did not reach statistical significance probably because of the small sample size. Diabetes and an ejection fraction lower than 35% are significant predictors for a worse prognosis.

Effect of early revascularisation in cardiogenic shock complicating acute myocardial infarction. A single center experience

BACKGROUND

Five to 10% of patients with acute myocardial infarction develop cardiogenic shock and the majority of these patients are expected to die within the first few weeks. In this study, we review our recent experience in the management of patients with cardiogenic shock complicating MI and examine the effect of early invasive revascularisation on mortality.

METHODS

Thirty-six consecutive patients who developed cardiogenic shock less than 48 h after MI were retrospectively evaluated and divided into two treatment groups. One group received early invasive revascularisation (n=24) and the other group had no early invasive revascularisation, but received similar conventional intensive care medical treatment (n=12).

RESULTS

Baseline characteristics and hemodynamic variables were similar in both groups. Apart from invasive revascularisation and the use of intra aortic balloon counterpulsation (IABP), treatment strategies did not differ between the two groups. Thirty-day mortality was 21% in the revascularised group of patients and 58% in the non-revascularised group (P<0.05).

CONCLUSIONS

Our data support previous observations suggesting that an aggressive treatment strategy including early invasive revascularisation and IABP is associated with improved short and long-term survival in patients with cardiogenic shock. Since early revascularisation appears safe with a considerable treatment benefit, this approach must be considered in patients with short shock duration early after MI.

[Elective primary angioplasty in cardiogenic shock: results from a single center]

INTRODUCTION

Cardiogenic shock is the leading cause of death among patients hospitalized for acute myocardial infarction. Conventional treatment for acute myocardial infarction does not achieve a better outcome in these patients, but prior studies with emergency revascularization by coronary angioplasty seem to provide encouraging results.

PATIENTS AND METHOD

A retrospective study of the clinical and angiographic results of elective primary angioplasty in 48 patients with cardiogenic shock complicating acute myocardial infarction of less than 12 hours is described. Intraaortic balloon counterpulsation was used in 79% of the patients. Patients with cardiogenic shock secondary to mechanical complications were excluded.

RESULTS

Angiographic success, defined as a residual stenosis < 50% and final TIMI flow >/= 2, was achieved in 85% of the culprit lesions, and stents were implanted in 76%. Multivessel angioplasty was performed in 25% of the patients, and abciximab was used in 35% of the cases. Mean time from the onset of symptoms to angioplasty was 7.4 +/- 3.1 hours. In-hospital survival was 58%, and was 54% at six months follow-up.

CONCLUSIONS

Emergency coronary revascularization with primary angioplasty and intracoronary stenting is effective in patients with acute myocardial infarction and cardiogenic shock. TIMI flow >/= 2 is achieved in most patients, and mortality is reduced when compared with conservative treatment in historical series.