Faculty Bibliography

BACKGROUND:Little is known about clinical outcomes of patients with acute myocardial infraction (AMI) complicated by cardiogenic shock (CS) requiring mechanical ventilation (MV). The aim of this study was to identify the characteristics, risk factors, and outcomes associated with the provision of MV in this specific high-risk population. METHODS:Patients with CS complicating AMI and multivessel coronary artery disease from the CULPRIT-SHOCK trial were included. We explored 30 days of clinical outcomes in patients not requiring MV, those with MV on admission, and those in whom MV was initiated within the first day after admission. RESULTS:Among 683 randomized patients included in the analysis, 17.4% received no MV, 59.7% were ventilated at admission and 22.8% received MV within or after the first day after admission. Patients requiring MV had a different risk-profile. Factors independently associated with the provision of MV on admission included higher body weight, resuscitation within 24 h before admission, elevated heart rate and evidence of triple vessel disease. CONCLUSIONS:Requiring MV in patients with CS complicating AMI is common and independently associated with mortality after adjusting for covariates. Patients with delayed MV initiation appear to be at higher risk of adverse outcomes. Further research is necessary to identify the optimal timing of MV in this high-risk population.

Cardiogenic shock (CS) is often complicated by respiratory failure, and more than 80% of patients with CS require respiratory support. Elevated filling pressures from left-ventricular (LV) dysfunction lead to alveolar pulmonary edema, which impairs both oxygenation and ventilation. The implementation of positive pressure ventilation (PPV) improves gas exchange and can improve cardiovascular hemodynamics by reducing preload and afterload of the LV, reducing mitral regurgitation and decreasing myocardial oxygen demand, all of which can help augment cardiac output and improve tissue perfusion. In right ventricular (RV) failure, however, PPV can potentially decrease preload and increase afterload, which can potentially lead to hemodynamic deterioration. Thus, a working understanding of cardiopulmonary interactions during PPV in LV and RV dominant CS states is required to safely treat this complex and high-acuity group of patients with respiratory failure. Herein, we provide a review of the published literature with a comprehensive discussion of the available evidence on the use of PPV in CS. Furthermore, we provide a practical framework for the selection of ventilator settings in patients with and without mechanical circulatory support, induction, and sedation methods, and an algorithm for liberation from PPV in patients with CS.

Chronic obstructive lung diseases and CVD are common conditions with a significant prevalence worldwide and substantial morbidity. There is a growing body of evidence that associates asthma as a potential risk factor for CVD, in particular, CAD, acute myocardial infarction and stroke. These observations appear to be stronger in patients with uncontrolled asthma and in women. Moreover, asthma that appears later in life has been also linked to CVD. The associations between asthma and CVD are incompletely understood, but chronic and systemic inflammation derived from the airways may have a role in the development of the atherosclerosis and hypercoagulable states. Additionally, eosinophils, smooth muscle factors, endothelial dysfunction and haemodynamic stress may be important factors that link asthma and CVD. These observations have raised clinical awareness and may identify asthmatics with a higher risk profile for CVD, opening an opportunity for potential interventions in the earlier stages of the disease.
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Despite increasing medical complexity in patients with heart failure (HF), there are limited data on incidence and outcomes for patients with HF needing respiratory support. This study sought to examine contemporary trends of respiratory support strategies among patients with HF. Using the National Inpatient Sample, we identified adults aged greater than 18 years hospitalized with a primary diagnosis of HF. We assessed for trends in the use of invasive mechanical ventilation (IMV) and noninvasive ventilation (NIV), length of stay, hospital costs, and in-hospital mortality. From 2002 to 2014, we identified 9,508,768 HF hospitalizations, which included 202,340 (2.13%) and 257,549 (2.71%) patients that required IMV and NIV, respectively. Over the study period, the proportion of HF patients requiring IMV significantly decreased (3.25% in 2002 to 1.56% in 2014) whereas the use of NIV significantly increased from 0.95% to 7.25% (p_trend <0.001 for both). In-hospital mortality significantly increased for IMV (31.5% in 2002 to 38.6% in 2014) recipients and decreased for patients requiring NIV (9.0% to 5.6%, p_trend <0.0001 for both). The average length of stay was nearly 7 days longer in the IMV group (12.2 days) and 2 days longer in the NIV group (6.8 days; p <0.001 for both). Hospital charges have nearly tripled for patients requiring IMV ($99,358 in 2014, p_trend <0.001) and doubled for those requiring NIV ($37,539 in 2014, p_trend <0.001). In conclusion, respiratory support strategies for patients with HF have significantly evolved with increasing use of NIV as compared with IMV. However, the in-hospital mortality associated with respiratory failure remains unacceptably high.

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.

Contemporary cardiac intensive care units (CICUs) provide care for an aging and increasingly complex patient population. The medical complexity of this population is partly driven by an increased proportion of patients with respiratory failure needing noninvasive or invasive positive pressure ventilation (PPV). PPV often plays an important role in the management of patients with cardiogenic pulmonary edema, cardiogenic shock, or cardiac arrest, and those undergoing mechanical circulatory support. Noninvasive PPV, when appropriately applied to selected patients, may reduce the need for invasive mechanical PPV and improve survival. Invasive PPV can be lifesaving, but has both favorable and unfavorable interactions with left and right ventricular physiology and carries a risk of complications that influence CICU mortality. Effective implementation of PPV requires an understanding of the underlying cardiac and pulmonary pathophysiology. Cardiologists who practice in the CICU should be proficient with the indications, appropriate selection, potential cardiopulmonary interactions, and complications of PPV.

BACKGROUND:Sodium nitroprusside is the preferred agent for the treatment of high blood pressure during acute aortic syndrome if blood pressure remains elevated after heart rate control with beta-blockers. The increasing cost of sodium nitroprusside in the USA led us to assess the efficacy and safety of intravenous clevidipine, a calcium channel blocker with quick onset of action, short half-life and significantly lower costs than sodium nitroprusside, in patients presenting with acute aortic syndrome. METHODS:We performed a retrospective chart review of consecutive patients admitted to the Cleveland Clinic Cardiac Intensive Care Unit from 2013-2016 with a diagnosis of acute aortic syndrome. Patients who received intravenous sodium nitroprusside were compared with those receiving intravenous clevidipine. The primary outcome was a significant difference in blood pressure at one, three and six hours. Secondary outcomes included time to achieving blood pressure target and in hospital mortality with rates of hypotension and bradycardia as safety endpoints. RESULTS:A total of 85 patients with suspected acute aortic pathology received clevidipine and 50 received sodium nitroprusside. Clinical and demographic characteristics were similar in both groups, except for a higher incidence of abdominal aortic aneurysm in the clevidipine group and for a trend towards higher use of labetalol in the clevidipine group. There were no significant differences in blood pressure or heart rate at one, three and six hours after starting either infusion. The rates of hypotension, bradycardia and in-hospital mortality did not differ. Time to achieve blood pressure control were also similar between groups. CONCLUSION/CONCLUSIONS:Intravenous clevidipine appears to be a safe and effective alternative to sodium nitroprusside for the management of high blood pressure during acute aortic dissection. In the USA, clevidipine could represent a cost effective therapy providing similar outcomes than sodium nitroprusside.