Cardiogenic shock without hypotension in acute myocardial infarction
Authors: Caldeira Da Rocha R , Picarra B , Fernandes R , Dias Claudio F , Carrington M , Pais J , Trinca M 
Published: April 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Cardiogenic Shock(CS)complicates 10%of Acute Myocardial Infarction(AMI), being the main cause for intra-hospital death in these patients.Although early revascularization has contributed to increase survival,mortality still presents high, being 40-50%.CS usually presents with inadequate cardiac output and persistent hypotension.However,after large AMI,peripheral hypoperfusion can occur with sustained or borderline systolic blood pressure(SBP).

Purpose
Characterize patients(pts)with CS after AMI in the absence of hypotension(defined as SBP &lt; 90mmHg),and assess impact in mortality.

Methods
We evaluated 528pts presenting with CS in context of AMI.We considered 2groups:Group 1-Pts who had SBP ≥90mmHg,without any inotropic drug or assist device and 2-Pts with SBP &lt; 90mmHg.We registered age,gender,co-morbidities,presentation,coronary anatomy and treatment strategies.We evaluated in-hospital mortality and complications:re-infarction,mechanical complications,high-grade atrioventricular block(AVB),sustained ventricular tachycardia,atrial fibrillation,resuscitated cardiac arrest and stroke.

Results
AMI presenting as Cardiogenic Shock without hypotension(CSWH)was found in 51%of pts(n = 272),of whom 69%were male.They were younger(between age of 45-64years old in 34%of cases vs 25%,p = 0.040)and had higher body mass index (27.3 ± 4.5vs 26 ± 4.1,p = 0.001).Hypertension was a similarly distributed comorbidity.In group 1,pts were previously more frequently under beta blocker medication (25.2%vs 17.7%,p = 0.047).In this group,mean left ventricular (LV)ejection fraction was 39 ± 13%,a quarter having severely depressed LV function(&lt;30%).Although STEMI was the most common presentation in both sets(73.5% vs 87.1%,p &lt; 0.001),NSTEMI was more prevalent in CSWH(23.9%vs12.1%,p &lt; 0.001).Those pts presented more,at admission,with dyspnea(14.9%vs5.5%,p &lt; 0.001)and in sinus rhythm(81.9%vs69%,p &lt; 0.001).In this group,ICU admission was less frequent(19.4%vs27.2%,p = 0.036),and only about half of pts were medicated with inotropic drugs(vs 78.1%,p &lt; 0.001).However,difference in intra-aortic balloon use wasn’t found.CSWH presented with multivessel disease in 63.8%of pts,being LAD more frequently the culprit vessel(42.4% vs 30.7%,p = 0.030),but fewer left main artery(LM)(4.2%vs14.0%,p = 0.003).Group 1 had fewer prevalence of vessel occlusion,which was particularly true for LM(3.8%vs11.5%,p = 0.015) and circumflex(12.4%vs20.7%,p = 0.047),and were less often submitted to revascularization.Group 1 had fewer AVB(9.8%vs22.4%,p &lt; 0.001).Rates of other complications were similar.In-hospital mortality was higher in classic CS(33.1% vs 43.8%, p= 0.012).

Conclusion
Cardiogenic Shock without hypotension was found in about half of pts with CS due to AMI.A majority of these were younger and globally had a less severe event and complications.Even though CSWH was associated with one third of in-hospital mortality,it was lower than in pts with hypotension.