Cardiogenic shock due to predominantly right ventricular failure complicating acute myocardial infarction

Invasive mechanical ventilation in cardiogenic shock complicating acute myocardial infarction: A contemporary Danish cohort analysis

PURPOSE

Invasive mechanical ventilation (IMV) is widely used in patients with cardiogenic shock following acute myocardial infarction (AMICS), but evidence to guide practice remains sparse. We sought to evaluate trends in the rate of IMV utilization, applied settings, and short term-outcome of a contemporary cohort of AMICS patients treated with IMV according to out-of-hospital cardiac arrest (OHCA) at admission.

METHODS

Consecutive AMICS patients receiving IMV in an intensive care unit (ICU) at two tertiary centres between 2010 and 2017. Data were analysed in relation to OHCA.

RESULTS

A total of 1274 mechanically ventilated AMICS patients were identified, 682 (54%) with OHCA. Frequency of IMV increased during the study period, primarily due to higher occurrence of OHCA admissions. Among 566 patients with complete ventilator data, positive-end-expiratory pressure, inspired oxygen fraction, and minute ventilation during the initial 24 h in ICU were monitored. No differences were observed between 30-day survivors and non-survivors with OHCA. In non-OHCA, these ventilator requirements were significantly higher among 30-day non-survivors (P for all<0.05), accompanied by a lower PaO2/FiO2 ratio (median 143 vs. 230, P < 0.001) and higher arterial lactate levels (median 3.5 vs. 1.5 mmol/L, P < 0.001) than survivors. Physiologically normal PaO2 and pCO2 levels were achieved in all patients irrespective of 30-day survival and OHCA status.

CONCLUSION

In the present contemporary cohort of AMICS patients, physiologically normal blood gas values were achieved both in OHCA and non-OHCA in the early phase of admission. However, increased demand of ventilatory support was associated with poorer survival only in non-OHCA patients.

Impact of Impella RP Versus Vasoactive Treatment on Right and Left Ventricular Strain in a Porcine Model of Acute Cardiogenic Shock Induced by Right Coronary Artery Embolization

Background The response of the left ventricle to cardiogenic shock (CS) caused by right ventricular (RV) infarction and the effect of treatment with either vasoactive treatment or Impella RP are not well described. We sought to determine RV and left ventricular longitudinal strain (LS) by echocardiography after initiation of either Impella RP or vasoactive treatment for CS induced by right coronary artery embolization. Methods and Results CS was induced with microsphere embolization in the right coronary artery in 20 pigs. Shock was defined as a reduction in cardiac output of ≥50% and/or an SvO2 <30%. At the time of CS either Impella RP or vasoactive treatment (norepinephrine and milrinone) was initiated. Echocardiography and conductance measures were obtained at baseline, when CS was present, and 30, 90, and 180 minutes after induction of CS. Of 20 animals, 14 completed the protocol and were treated with either vasoactive treatment (n=7) or Impella RP (n=7); 6 animals died (3 in each group). In the RV there was a significantly higher LS with the vasoactive treatment compared with Impella RP (-7.6% [4.5] to -6.0% [5.2] vs -4.5% [6.6] to -14.2% [10.6]; P<0.006). Left ventricular LS improved with both treatments compared with shock, but with a larger effect (-9.4% [3.2] to -17.9% [3.6]) on LS with vasoactive treatment than Impella RP (-9.8% [3.1] to -12.3% [4.6]; P<0.001). We found a significant correlation between stroke work and RV LS (r=-0.60, P<0.001) and left ventricular LS (r=-0.62, P<0.001). Conclusions We found significantly higher hemodynamic effects with vasoactive treatment compared with Impella RP in both the RV and left ventricular but at a cost of increased stroke work.

Keep the Right in Mind-A Focused Approach to Right Ventricle-Predominant Cardiogenic Shock

Cardiogenic shock (CS) remains a highly lethal condition despite many efforts and new interventions. Patients presenting with a rapid onset of hemodynamic instability and subsequent collapse require prompt and appropriate multimodality treatment. Multiple etiologies can lead to heart failure and subsequent shock. As the case prevalence of heart failure increases worldwide, it is of great importance to explore all manners and protocols of presentation and treatment present. With research primarily focusing on CS due to cardiac left-sided pathology, few assessments of right-sided pathology and the subsequent clinical state and treatment have been conducted. This review aims to present an in-depth assessment of the currently available literature, assessing the pathophysiology, presentation and management of CS patients due to right heart failure.

Outcomes in cardiogenic shock: the role of surrogate endpoints

PURPOSE OF REVIEW

Early revascularization, invasive hemodynamic profiling, and initiation of temporary mechanical circulatory support (MCS) have all become routine components of cardiogenic shock (CS) management. Despite this evolution in clinical practice, patient selection and timing of treatment initiation remain a significant barrier to achieving sustained improvement in CS outcomes. Recent efforts to standardize CS management, through the development of treatment algorithms, have relied heavily on surrogate endpoints to drive therapeutic decisions. The present review aims to provide an overview of the basis of evidence for those surrogate endpoints commonly employed in clinical trials and CS management algorithms.

RECENT FINDINGS

Recent publications from both observational and randomized cohorts have demonstrated the utility of surrogate endpoints in risk stratifying patients with CS. In particular, invasive hemodynamics using pulmonary artery catheters to guide initiation and weaning of MCS, biochemical markers that portend imminent end-organ failure, and clinical risk scores that combine multiple hemodynamic and laboratory parameters have demonstrated an ability to prognosticate outcomes in patients with CS.

SUMMARY

Although further validation is necessary, multiple clinical, hemodynamic, and biochemical markers have demonstrated utility as surrogate endpoints in CS, and will undoubtedly assist physicians in clinical decision-making.

Hyperlactataemia and acid-base disturbances in normotensive patients with acute heart failure

AIMS

Acute heart failure (AHF) may be associated with low-tissue perfusion and/or hypoxaemia leading to increased lactate levels and acid-base perturbations. Few data are available on the clinical significance of elevated lactate levels and primary acid-base disorders in the setting of AHF.

METHODS AND RESULTS

Arterial blood gas was obtained at admission in 4012 normotensive (systolic blood pressure ≥ 90 mmHg) patients with AHF. The association between lactate levels and acid-base status and in-hospital mortality was determined using multivariable logistic regression. Hyperlactataemia (>2 mmol/L) was present in 38.0% of patients and was strongly associated with markers of sympathetic activation, such as hyperglycaemia. Hyperlactataemia was present in 31.0%, 43.7%, and 42.0% of patients with normal pH, acidosis, and alkalosis, respectively. In-hospital mortality occurred in 16.4% and 11.1% of patients with and without hyperlactataemia [adjusted odds ratio (OR) 1.49; 95% confidence interval (CI) 1.22-1.82, P < 0.0001]. Compared with normal pH, the OR for in-hospital mortality was 2.48 (95% CI 1.95-3.16, P < 0.0001) in patients with acidosis and 1.77 (95% CI 1.32-2.26, P < 0.0001) in patients with alkalosis. The risk for in-hospital mortality was high with acidosis (18.1%) or alkalosis (10.4%) even with normal lactate. The most common primary acid-base disturbances included metabolic acidosis, respiratory acidosis, and metabolic alkalosis with respiratory acidosis having the highest risk for in-hospital mortality.

CONCLUSION

Hyperlactataemia was common in patients without hypotension and was associated with increased risk for in-hospital mortality. Hyperlactataemia is not associated with any specific acid-base disorder. Acute heart failure patients also present with diverse acid-base disorders portending increased in-hospital mortality.

Interventional treatment of acute myocardial infarction-related cardiogenic shock

PURPOSE OF REVIEW

Acute revascularization is with some evidence the only intervention proven to improve the prognosis in myocardial infarction-related cardiogenic shock but several interventions are continuously being investigated in order to increase survival among these patients. In this review, several aspects related to the interventional treatment of cardiogenic shock are discussed chronologically from symptom debut to leaving the cardiac catheterization laboratory.

RECENT FINDINGS

In the randomized CULPRIT-SHOCK trial, a culprit-only revascularization strategy was reported superior to immediate complete revascularization among patients with multivessel disease. Recent large-scale observational data underline the marked prognostic importance of time from medical contact to revascularization in acute myocardial infarction-related cardiogenic shock. Moreover, studies suggest a potential beneficial effect of a transradial vascular access as well as early initialization of mechanical circulatory support in carefully selected patients. This, however, needs further validation.

SUMMARY

Acute revascularization remains a crucial part of the initial management of acute myocardial infarction-related cardiogenic shock. Among cardiogenic shock patients presenting with multivessel disease, a culprit-only approach should be the routine strategy. Time to revascularization plays a crucial role in the setting of cardiogenic shock, why prehospital optimization and triaging may be the most important factors in order to improve prognosis in AMI-related cardiogenic shock.

Impella RP Versus Pharmacologic Vasoactive Treatment in Profound Cardiogenic Shock due to Right Ventricular Failure

The aim was to translationally compare a pharmacologic strategy versus treatment with the Impella RP in profound RV cardiogenic shock (CS). The pigs were allocated to either vasoactive therapy with norepinephrine (0.10 μg/kg/min) for the first 30 min, supplemented by an infusion of milrinone (0.4 μg/kg/min) for additional 150 min, or treatment with the Impella RP device for 180 min. Total RV workload (Pressure-volume-area × heart rate*10³(mmHg/min)) remained unaffected upon treatment with the Impella RP and increased in the vasoactive group (CS 179[147;228] to norepinephrine 268[247;306](p = 0.002 compared to Impella RP) and norepinephrine + milrinone 366[329;422] (p = 0.002 compared to Impella RP). A trend towards higher venous cerebral oxygen saturation was observed with norepinephrine than Impella RP (Impella RP 51[47;61]% vs norepinephrine 62[57;71]%; p = 0.07), which became significantly higher with the addition of milrinone (Impella RP 45[32;63]% vs norepinephrine + milrinone 73[66;81]%; p = 0.002). The Impella RP unloaded the failing RV. In contrast, vasoactive treatment led to enhanced cerebral venous oxygen saturation.