Faculty Bibliography

BACKGROUND:Temporary mechanical circulatory support (MCS) devices provide hemodynamic assistance for shock refractory to pharmacological treatment. Most registries have focused on single devices or specific etiologies of shock, limiting data regarding overall practice patterns with temporary MCS in cardiac intensive care units. METHODS:The CCCTN (Critical Care Cardiology Trials Network) is a multicenter network of tertiary CICUs in North America. Between September 2017 and September 2018, each center (n=16) contributed a 2-month snapshot of consecutive medical CICU admissions. RESULTS:Of the 270 admissions using temporary MCS, 33% had acute myocardial infarction-related cardiogenic shock (CS), 31% had CS not related to acute myocardial infarction, 11% had mixed shock, and 22% had an indication other than shock. Among all 585 admissions with CS or mixed shock, 34% used temporary MCS during the CICU stay with substantial variation between centers (range: 17%-50%). The most common temporary MCS devices were intraaortic balloon pumps (72%), Impella (17%), and veno-arterial extracorporeal membrane oxygenation (11%), although intraaortic balloon pump use also varied between centers (range: 40%-100%). Patients managed with intraaortic balloon pump versus other forms of MCS (advanced MCS) had lower Sequential Organ Failure Assessment scores and less severe metabolic derangements. Illness severity was similar at high- versus low-MCS utilizing centers and at centers with more advanced MCS use. CONCLUSIONS:There is wide variation in the use of temporary MCS among patients with shock in tertiary CICUs. While hospital-level variation in temporary MCS device selection is not explained by differences in illness severity, patient-level variation appears to be related, at least in part, to illness severity.

Importance/UNASSIGNED:Single-center and claims-based studies have described substantial changes in the landscape of care in the cardiac intensive care unit (CICU). Professional societies have recommended research to guide evidence-based CICU redesigns. Objective/UNASSIGNED:To characterize patients admitted to contemporary, advanced CICUs. Design, Setting, and Participants/UNASSIGNED:This study established the Critical Care Cardiology Trials Network (CCCTN), an investigator-initiated multicenter network of 16 advanced, tertiary CICUs in the United States and Canada. For 2 months in each CICU, data for consecutive admissions were submitted to the central data coordinating center (TIMI Study Group). The data were collected and analyzed between September 2017 and 2018. Main Outcomes and Measures/UNASSIGNED:Demographics, diagnoses, management, and outcomes. Results/UNASSIGNED:Of 3049 participants, 1132 (37.1%) were women, 797 (31.4%) were individuals of color, and the median age was 65 years (25th and 75th percentiles, 55-75 years). Between September 2017 and September 2018, 3310 admissions were included, among which 2557 (77.3%) were for primary cardiac problems, 337 (10.2%) for postprocedural care, 253 (7.7%) for mixed general and cardiac problems, and 163 (4.9%) for overflow from general medical ICUs. When restricted to the initial 2 months of medical CICU admissions for each site, the primary analysis population included 3049 admissions with a high burden of noncardiovascular comorbidities. The top 2 CICU admission diagnoses were acute coronary syndrome (969 [31.8%]) and heart failure (567 [18.6%]); however, the proportion of acute coronary syndrome was highly variable across centers (15%-57%). The primary indications for CICU care included respiratory insufficiency (814 [26.7%]), shock (643 [21.1%]), unstable arrhythmia (521 [17.1%]), and cardiac arrest (265 [8.7%]). Advanced CICU therapies or monitoring were required for 1776 patients (58.2%), including intravenous vasoactive medications (1105 [36.2%]), invasive hemodynamic monitoring (938 [30.8%]), and mechanical ventilation (652 [21.4%]). The overall CICU mortality rate was 8.3% (95% CI, 7.3%-9.3%). The CICU indications that were associated with the highest mortality rates were cardiac arrest (101 [38.1%]), cardiogenic shock (140 [30.6%]), and the need for renal replacement therapy (51 [34.5%]). Notably, patients admitted solely for postprocedural observation or frequent monitoring had a mortality rate of 0.2% to 0.4%. Conclusions and Relevance/UNASSIGNED:In a contemporary network of tertiary care CICUs, respiratory failure and shock predominated indications for admission and carried a poor prognosis. While patterns of practice varied considerably between centers, a substantial, low-risk population was identified. Multicenter collaborative networks, such as the CCCTN, could be used to help redesign cardiac critical care and to test new therapeutic strategies.

Background Clinical investigations of shock in cardiac intensive care units (CICUs) have primarily focused on acute myocardial infarction (AMI) complicated by cardiogenic shock (AMICS). Few studies have evaluated the full spectrum of shock in contemporary CICUs. Methods and Results The Critical Care Cardiology Trials Network is a multicenter network of advanced CICUs in North America. Anytime between September 2017 and September 2018, each center (n=16) contributed a 2-month snap-shot of all consecutive medical admissions to the CICU. Data were submitted to the central coordinating center (TIMI Study Group, Boston, MA). Shock was defined as sustained systolic blood pressure <90 mm Hg with end-organ dysfunction ascribed to the hypotension. Shock type was classified by site investigators as cardiogenic, distributive, hypovolemic, or mixed. Among 3049 CICU admissions, 677 (22%) met clinical criteria for shock. Shock type was varied, with 66% assessed as cardiogenic shock (CS), 7% as distributive, 3% as hypovolemic, 20% as mixed, and 4% as unknown. Among patients with CS (n=450), 30% had AMICS, 18% had ischemic cardiomyopathy without AMI, 28% had nonischemic cardiomyopathy, and 17% had a cardiac cause other than primary myocardial dysfunction. Patients with mixed shock had cardiovascular comorbidities similar to patients with CS. The median CICU stay was 4.0 days (interquartile range [IQR], 2.5-8.1 days) for AMICS, 4.3 days (IQR, 2.1-8.5 days) for CS not related to AMI, and 5.8 days (IQR, 2.9-10.0 days) for mixed shock versus 1.9 days (IQR, 1.0-3.6) for patients without shock ( P<0.01 for each). Median Sequential Organ Failure Assessment scores were higher in patients with mixed shock (10; IQR, 6-13) versus AMICS (8; IQR, 5-11) or CS without AMI (7; IQR, 5-11; each P<0.01). In-hospital mortality rates were 36% (95% CI, 28%-45%), 31% (95% CI, 26%-36%), and 39% (95% CI, 31%-48%) in AMICS, CS without AMI, and mixed shock, respectively. Conclusions The epidemiology of shock in contemporary advanced CICUs is varied, and AMICS now represents less than one-third of all CS. Despite advanced therapies, mortality in CS and mixed shock remains high. Investigation of management strategies and new therapies to treat shock in the CICU should take this epidemiology into account.

PURPOSE OF REVIEW/OBJECTIVE:Just over four decades ago, the management of coronary artery disease (CAD) witnessed a major breakthrough with the advent of minimally invasive treatment modalities like angioplasty followed by coronary stenting. Dr. Andreas Gruentzig pioneered this field in 1977 by adding a balloon to the Dotter catheter. From its inception, he was cognizant of the need for measuring pressures before and after balloon inflation in the treated coronary artery, device placement in the treated coronary artery. However, for decades subsequently, emphasis was placed primarily on preprocedural non-invasive tests and angiographic assessment of lesions based on percent diameter stenosis to guide therapeutic interventions. We review the progress of these physiologic advancements in management over the last 20 years, as well as the current state and prospects for the future. RECENT FINDINGS/RESULTS:More recently, clinical features heavily drive the decision whether or not to stent the diseased segment. A little more than two decades ago, a new approach to facilitate the decision whether or not to intervene on intermediate stenoses began to evolve. It became clear that other features besides angiography are important when considering benefit of mechanical intervention. The emphasis shifted to assessment of the physiological significance of coronary lesions, rather than solely anatomical identification of lesions at angiography. Physiological assessments have served to better discriminate potentially flow-limiting lesions, utilizing cutoff measurements to determine which patients would benefit from intervention in addition to medical therapy. We have found that there is still need for arrival at a consensus as regards the best practice in the context of physiological assessment of serial stenotic lesions, but that studies do show that techniques currently available are non-inferior to each other, and highly effective.

Therapeutic hypothermia, the standard for post-resuscitation care of out-of-hospital sudden cardiac arrest (SCA), is an area that the most recent resuscitation guidelines note "has not been studied adequately." We conducted a two-phase study examining the role of intra-arrest hypothermia for out-of-hospital SCA, first standardizing the resuscitation and transport of patients to resuscitation centers where post-resuscitation hypothermia was required and then initiating hypothermia during out-of-hospital resuscitation efforts. The primary end points were return of spontaneous circulation (ROSC), sustained ROSC, survival to hospital admission, and survival to discharge. Comparing the cohort of standard hospital-initiated hypothermia (Phase I) with the prehospital-initiated hypothermia via large-volume ice-cold saline (LVICS) infusion (Phase II), no difference was noted for any end point: ROSC (56.4% vs. 53.4%, p = 0.51; 95% confidence interval [CI]: -5.7 to 11.4), sustained ROSC (46.9% vs. 42.8%, p = 0.38; 95% CI: -4.7 to 12.4), hospital admission (44.7% vs. 37.7%, p = 0.13; 95% CI: -1.9 to 15.4), hospital discharge among those surviving to admission (40.0% vs. 28.0%, p = 0.08; 95% CI: -1.5 to 27.8), or neurological outcome among those surviving to discharge (76.0% vs. 71.4%, p = 0.73; 95% CI: -26.9 to 38.7). Patients presenting in ventricular fibrillation were more likely to survive to hospital discharge in both phases, although a trend toward worsened early outcomes (ROSC, sustained ROSC, and survival to admission) with intra-arrest hypothermia was noted in this subgroup. Multivariable regression analyses failed to demonstrate any survival benefit associated with the intra-arrest initiation of hypothermia via LVICS. Our study, the largest study of intra-arrest initiation of hypothermia published to date, failed to demonstrate any effect on survival for out-of-hospital SCA patients, confirming findings of previously published smaller studies. We therefore do not recommend the use of intra-arrest cooling via LVICS infusion as part of routine out-of-hospital SCA resuscitative efforts.

BACKGROUND: The 2013 American College of Cardiology Foundation/American Heart Association ST-segment elevation myocardial infarction (STEMI) guidelines have shifted focus from door-to-balloon (D2B) time to the time from first medical contact to device activation (contact-to-device time [C2D] ). HYPOTHESIS: This study investigates the impact of prehospital wireless electrocardiogram transmission (PHT) on reperfusion times to assess the impact of the new guidelines. METHODS: From January 2009 to December 2012, data were collected on STEMI patients who received percutaneous coronary interventions; 245 patients were included for analysis. The primary outcome was median C2D time in the PHT group and the secondary outcome was D2B time. RESULTS: Prehospital wireless electrocardiogram transmission was associated with reduced C2D times vs no PHT: 80 minutes (interquartile range [IQR], 64-94) vs 96 minutes (IQR, 79-118), respectively, P < 0.0001. The median D2B time was lower in the PHT group vs the no-PHT group: 45 minutes (IQR, 34-56) vs 63 minutes (IQR, 49-81), respectively, P < 0.0001. Multivariate analysis showed PHT to be the strongest predictor of a C2D time of <90 minutes (odds ratio: 3.73, 95% confidence interval: 1.65-8.39, P = 0.002). Female sex was negatively predictive of achieving a C2D time <90 minutes (odds ratio: 0.23, 95% confidence interval: 0.07-0.73, P = 0.01). CONCLUSIONS: In STEMI patients, PHT was associated with significantly reduced C2D and D2B times and was an independent predictor of achieving a target C2D time. As centers adapt to the new guidelines emphasizing C2D time, targeting a shorter D2B time (<50 minutes) is ideal to achieve a C2D time of <90 minutes.