First EDition: Mobile Stroke Units Becoming More Common, more

Waiting for More Data

Despite these advances and the steady recent growth of MSUs, significant skepticism remains. “While mobile stroke units seem like a good idea and there is genuine hope that they will improve outcomes for selected stroke patients, there is not yet any evidence that this is the case,” wrote Bryan Bledsoe, DO, in a January 2017 editorial in the Journal of Emergency Medical Services. “They are expensive and financially nonsustainable. Without widespread deployment, they stand to benefit few, if any, patients. The money spent on these devices would be better spent on improving the current EMS system, including paramedic education, the availability of stroke centers, and on the early recognition of ELVO [emergent large vessel occlusion] strokes,” wrote Dr Bledsoe, professor of emergency medicine at the University of Nevada in Las Vegas.

Two other experts voiced concerns about MSUs in an editorial that accompanied a Cleveland Clinic report in March.⁴ “Even if MSUs meet an acceptable societal threshold for cost-effectiveness, cost-efficiency may prove a taller order to achieve return on investment for individual health systems and communities,” wrote Andrew M. Southerland, MD, and Ethan S. Brandler, MD. They cited the Cleveland report, which noted that the group’s first 100 MSU-treated patients came from a total of 317 MSU deployments and included 217 trips that were canceled prior to the MSU’s arrival at the patient’s location. In Berlin’s initial experience, more than 2,000 MSU deployments led to 200 tPA treatments and 349 cancellations before arrival, noted Dr Southerland, a neurologist at the University of Virginia in Charlottesville, and Dr Brandler, an emergency medicine physician at Stony Brook (NY) University.

“Hope remains that future trials may demonstrate the ultimate potential of mobile stroke units to improve long-term outcomes for more patients by treating them more quickly and effectively. In the meantime, ongoing efforts are needed to streamline MSU cost and efficiency,” they wrote.

Proponents of MSUs agree that what’s needed now are more data to prove efficacy and cost-effectiveness, as well as better integration into EMS programs. The first opportunity for documenting the clinical impact of MSUs on larger numbers of US patients may be from the BEnefits of Stroke Treatment Delivered using a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services (BEST-MSU) Study, funded by the Patient-Centered Outcomes Research Institute. This study is collecting data from the MSU programs in Denver, Houston, and Memphis. Although currently designed to enroll 697 patients, Dr Grotta said he hopes to bring the number up to 1,000 patients.

“We are following the health care use and its cost for every enrolled MSU and conventional patient for 1 year,” Dr Grotta explained in an interview. He hopes these results will provide the data needed to move MSUs from investigational status to routine and reimbursable care.

References

1. Kunz A, Ebinger M, Geisler F, et al. Functional outcomes of pre-hospital thrombolysis in a mobile stroke treatment unit compared with conventional care: an observational registry study. Lancet Neurol. 2016;15(10):1035-1043. doi:10.1016/S1474-4422(16)30129-6.

2. Taqui A, Cerejo R, Itrat A, et al; Cleveland Pre-Hospital Acute Stroke Treatment (PHAST) Group. Reduction in time to treatment in prehospital telemedicine evaluation and thrombolysis. Neurology. 2017 March 8. [Epub ahead of print]. doi:10.1212/WNL.0000000000003786.

3. Ramadan AR, Denny MC, Vahidy F, et al. Agreement among stroke faculty and fellows in treating ischemic stroke patients with tissue-type plasminogen activator and thrombectomy. Stroke. 2017;48(1):222-224. doi:10.1161/STROKEAHA.116.015214.

4. Southerland AM, Brandler ES. The cost-efficiency of mobile stroke units: Where the rubber meets the road. Neurology. 2017 Mar 8. [Epub ahead of print]. doi:10.1212/WNL.0000000000003833.

Pulmonary Embolism Common in Patients With Acute Exacerbations of COPD

JIM KLING

FRONTLINE MEDICAL NEWS

About 16% of patients with unexplained acute exacerbations of chronic obstructive pulmonary disease (AECOPD) had an accompanying pulmonary embolism (PE), usually in regions that could be targeted with anticoagulants, according to a new systematic review and meta-analysis.

Approximately 70% of AECOPD cases develop in response to an infection, but about 30% of the time, an AE has no clear cause, the authors said in a report on their research. There is a known biological link between inflammation and coagulation, which suggests that patients experiencing AECOPD may be at increased risk of PE.

The researchers reviewed and analyzed seven studies, comprising 880 patients. Among the authors’ reasons for conducting this research was to update the pooled prevalence of PE in AECOPD from a previous systematic review published in Chest in 2009.

The meta-analysis revealed that 16.1% of patients with AECOPD were also diagnosed with PE (95% confidence interval [CI], 8.3%-25.8%). There was a wide range of variation between individual studies (prevalence 3.3%-29.1%). In six studies that reported on deep vein thrombosis (DVT), the pooled prevalence of DVT was 10.5% (95% CI, 4.3%-19.0%).

Five of the studies identified the PE location. An analysis of those studies showed that 35% were in the main pulmonary artery, and 31.7% were in the lobar and interlobar arteries. Such findings “[suggest] that the majority of these embolisms have important clinical consequences,” the authors wrote.

The researchers also looked at clinical markers that accompanied AECOPD and found a potential signal with respect to pleuritic chest pain. One study found a strong association between pleuritic chest pain and AECOPD patients with PE (81% vs 40% in those without PE). A second study showed a similar association (24% in PE vs 11.5% in non-PE patients), and a third study found no significant difference.

The presence of PE was also linked to hypotension, syncope, and acute right failure on ultrasonography, suggesting that PE may be associated with heart failure.

Patients with PE were less likely to have symptoms consistent with a respiratory tract infection. They also tended to have higher mortality rates and longer hospitalization rates compared with those without PE.

The meta-analysis had some limitations, including the heterogeneity of findings in the included studies, as well as the potential for publication bias, since reports showing unusually low or high rates may be more likely to be published, the researchers noted. There was also a high proportion of male subjects in the included studies.

Overall, the researchers concluded that PE is more likely in patients with pleuritic chest pain and signs of heart failure, and less likely in patients with signs of a respiratory infection. That information “might add to the clinical decision-making in patients with an AECOPD, because it would be undesirable to perform [CT pulmonary angiography] in every patient with an AECOPD,” the researchers wrote.