Implications of Prevalent Noncardiac Disease in the Cardiac ICU

Marlene Busko

April 24, 2017

CHARLOTTESVILLE, VA — Half of >1000 patients of admitted to the cardiac intensive care unit (ICU) at a major tertiary-care center over about 1 year also had acute respiratory failure, acute kidney injury, or sepsis[1].

Those with lung or kidney failure also had longer ICU stays, and those with lung or kidney failure or sepsis showed up to four times the risk of dying in the hospital, report Dr Eric M Holland and Dr Travis J Moss (University of Virginia Health System, Charlottesville), based on their review of >1000 consecutive cardiac ICU admissions for which ECG data were available.

Sepsis occurred in 16% of all admissions, and acute kidney failure and acute respiratory failure each were seen in 30% of the cohort, "which is staggering if you really think about the burden that has on these patients in the cardiac-ICU setting," Holland told heartwire from Medscape.

The "once-predominant postacute coronary syndrome observation unit has evolved into a heterogeneous population rich in both cardiovascular and noncardiovascular illnesses," the group points out in their report in the April 25, 2017 issue of the Journal of the American College of Cardiology.

Yet "cardiologists staff most cardiac ICUs and have relatively limited experience treating the most severe forms of hospital-acquired noncardiovascular conditions compared with intensivists who staff medical ICUs."

The current analysis "really drives the point home that these patients are very complex and very sick and shows how much those noncardiovascular conditions affect hard outcomes like mortality," Holland said when interviewed.

"The extent of comorbidities demands that clinicians caring for patients in the cardiac ICU have the competencies necessary to manage patients with both cardiovascular and noncardiovascular conditions," write Holland and Moss.

"Sea Change" in CV Medical Education

Indeed, "your cardiac ICU is not your grandfather's 'coronary care unit,'  " observe Dr David M Dudzinski and Dr James L Januzzi Jr (Massachusetts General Hospital, Boston) in an accompanying editorial[2].

Patients with acute MI "are now frequently managed in non–intensive-care-unit settings, whereas the contemporary cardiac ICU serves a considerably more heterogeneous population of patients."

The study, they write, "confirms what is widely known: cardiac ICU patients are a vulnerable lot, with poor physiological and cardiac reserve and numerous comorbidities, and thus are less able to tolerate critical illness."

The current study has "substantial significance" for the cardiologist managing complex patients in the cardiac ICU, they write, calling for a "sea change in cardiovascular medical education" in which cardiology fellows will receive more training in critical care.

"More integrated management with critical-care specialists ('intensivists') must be championed as the new standard of practice in the cardiac ICU," with greater "focus on prevention of iatrogenic harms (eg, ventilator-associated pneumonia, catheter-related bloodstream infection) central to management in a modern ICU setting."

Noncardiac Diagnoses and Outcomes

There is very little available information on how noncardiovascular comorbidities affect length of hospital stay, mortality, and readmission in patients with advanced cardiac disease who are admitted to the cardiac ICU, according to Holland and Moss.

In their review of 1042 patients admitted to the 10-bed cardiac ICU, representing all during the year with available ECG data, 70% were admitted for a medical reason. The rest were admitted after scheduled surgery (26%) such as transcatheter aortic-valve replacement or after unscheduled surgery (4%).

A quarter of the patients had a primary ACS diagnosis, including 14% with non-ST-segment-elevation ACS and 11% with STEMI; 15% had a primary diagnosis of acute heart-failure exacerbation; and 10% had valvular disease (10%).

A total of 14% of patients had a noncardiovascular illness, a third of that sepsis, as their primary diagnosis. However, 16% of the total cohort had sepsis as a primary or secondary condition.

So, "presumably sepsis developed during the cardiac ICU course, possibly secondary to cardiac procedures or iatrogenic harms, including catheter-related or ventilator-related infections," Dudzinzki and Januzzi observe.

The patients stayed in the cardiac ICU for a median of 2 days and then stayed in the hospital for a median of another 4 days. Patients who had acute kidney injury or acute respiratory failure stayed in the cardiac ICU for an extra 5.5 days and 6.7 days, respectively.

A total of 7% of the patients died in the cardiac ICU and 12% died in the hospital.

Acute kidney injury, acute respiratory failure, and sepsis were each significantly independent predictors of in-hospital mortality. Age, Oxford Acute Severity of Illness Score, hemorrhage, cardiogenic shock, and cardiac arrest were also significant independent predictors of in-hospital death.

Noncardiac Predictors of In-Hospital Mortality, 1042 Cardiac ICU Patients

Condition Odds ratio (95% CI)
Acute kidney injury 1.85 (1.15–2.98)
Acute respiratory failure 3.64 (2.17–6.11)
Sepsis 2.09 (1.22–3.58)

Of the 920 patients who survived to hospital discharge, 19% were readmitted to the hospital within 30 days, and 49% of these readmissions were to the cardiac ICU.

"The importance of sepsis after [cardiac] ICU admission cannot be discounted," Dudzinski and Januzzi stress. "Because sepsis affects one-sixth of cardiac ICU patients and carries a twofold risk of in-cardiac ICU mortality," they write, "cardiologists must be aware of the potential sources, etiology, trajectory, and microbiology of sepsis in the cardiac ICU."

Holland, Moss, Dudzinski, and Januzzi report that they have no relevant financial relationships.

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