According to Lisa Wheeler, a research coordinator at Vanderbilt University in Nashville, TN, other health conditions underlying pulmonary hypertension (PH) can actually cause more deaths than the lung disease in critically ill patients. This finding necessitates a new direction in the care of subgroups of PH in intensive care units (ICUs). Wheeler presented the results at the Society of Critical Care Medicine 43rd Critical Care Congress.
Pulmonary hypertension is classified into 5 groups. Pulmonary arterial hypertension (PAH) is often referred to as group 1 pulmonary hypertension. PH can be related to left heart disease, lung disease or hypoxia, blood clots and a number of other factors. Group 1 patients tend to fare poorly in ICUs, however, very few studies have looked at the fate of patients in the other groups. Wheeler and colleagues did just that by looking at readmission rates by types of pulmonary hypertension of 450 PH patients over a 30-month period. They discovered 79 patients with 122 admissions to the ICU. The rate of readmission varied in the different groups.
Readmission Rate by Type of Pulmonary Hypertension
- Group 1 – 28 percent
- Left heart disease – 25 percent
- Lung disease or hypoxia – 0 percent
- Blood clots – 50 percent
- Multifactorial – 46 percent
- All-causes – 32 percent
Since sample sizes were small, the researchers combined patients with left heart disease, lung disease or hypoxia, blood clots, and other factors into a single group. Wheeler notes, “We actually thought that the group 1 patients would do worse because they have really terrible heart problems. What we found is that they actually don’t do worse, and the length of stay was shorter.” However, outcomes were not significantly different between group 1 patients and those in the combined group.
Outcomes Group 1 Combined Group P Value
Length of stay (days) 9 10 0.41
ICU mortality (%) 13 10 0.73
Long-term mortality (%) 40 36 0.82
Wheeler notes, on average, group 1 patients were younger (46.9 years) than combined patients (53.5 years). She believes this may have played a role in length of stay. Long-term causes of death (both in the ICU and during follow-up) were different in the 2 groups. More patients in group 1 died of PH than in the combined group (81% vs 42%; P = 0.05).
Wheeler points out, many group 1 patients died of PH in the ICU, but no patients in the combined group did. Combined patients in the ICU died from different causes such as kidney failure and bleeding. “It made us think that we need to look at how the other patients are treated. Maybe the focus needs to be not on their primary hypertension, but on the condition underlying their pulmonary hypertension.”
Charles Hobson, MD, research assistant professor of surgery at the University of Florida in Gainesville and session moderator, posed a question asking if the Wheeler and colleagues had done any regression analysis to determine adjusted causes of the outcomes. Wheeler replied, “Not yet.” She knew that the sample size was small but “it was a lot for pulmonary hypertension because there are not that many patients with this condition”. Hobson also asked if Wheeler could comment about differences in the way patients were treated. Wheeler responded by saying that many patients in the combined group “don’t get PH drugs because these drugs would be contraindicated, especially in left heart disease patients.”