Mobile cardiac catheterization registry: report of the first 1,001 patients

Mobile cardiac catheterization laboratories increase use of cardiac care in women and African Americans

BACKGROUND

Women and minorities traditionally have shown less use of diagnostic cardiac catheterization. We sought to determine whether mobile cardiac catheterization laboratories may increase the use of catheterization among women and minorities by bringing the technology to remote communities.

METHODS

We collected data on consecutive patients undergoing cardiac catheterization at mobile laboratories located at 15 community hospitals in North Carolina and Virginia from 1994 to 2005. These data were compared with those from similar consecutive outpatients at the Duke University Medical Center (Durham, NC) cardiac catheterization laboratory over the same period. Logistic regression modeling techniques were used to determine which patient factors were associated with the decision to use a particular facility.

RESULTS

Women comprised 48% of the patients undergoing cardiac catheterization via mobile laboratory versus 42% of those patients receiving outpatient catheterization at the medical center laboratory (P < .001). All racial minorities combined (African American, Hispanic, Native American, Asian, and other) made up 27% of the mobile laboratory population undergoing catheterization versus 21% of the medical center outpatients who underwent the procedure (P < .001). Most minorities were African American. The most important predictor of patients receiving catheterization via a mobile laboratory rather than at the medical center catheterization laboratory was distance to the nearest mobile facility. Within a home-to-mobile laboratory range of approximately 35 miles, the odds of being treated at a mobile laboratory increased greatly the closer the patient lived to the facility.

CONCLUSIONS

The strongest predictor of mobile laboratory use was the patient's proximity to the mobile facility. When compared with a traditional tertiary referral outpatient hospital setting, a greater percentage of women and African Americans received cardiac catheterization at mobile laboratories. The availability of mobile laboratories may increase the use of cardiac procedures among women and African Americans.

The safety of performing diagnostic cardiac catheterizations in a mobile catheterization laboratory at primary care hospitals

The benefits of mobile cardiac catheterization laboratories include keeping patients closer to their families, communities, local hospitals, and primary care physicians while receiving services comparable to those available at tertiary centers. However, there are very few studies regarding the safety of performing cardiac catheterization in mobile laboratories at remote locations. Thus, the authors performed an observational study of 1,775 consecutive patients undergoing a diagnostic cardiac catheterization in a mobile catheterization laboratory at primary care hospitals served by the Appleton Heart Institute (AHI) from August 1, 1991, to December 31, 1998. Twenty-three percent (1,775/7,637) of all AHI diagnostic cases in this time period were performed in the mobile catheterization laboratory. Urgent transfer to the tertiary care facility via ambulance or helicopter was used for 2.3% of patients (n = 41). The overall complication rate was 1.2% (n = 21). Of the patients who underwent cardiac catheterization in the mobile laboratory, 32.6% (n = 579) were subsequently referred for interventional or surgical revascularization. There were no deaths. Cardiac catheterizations can be performed safely in a mobile laboratory at primary care hospitals, provided that immediate transfer is available for those in need of urgent intervention or revascularization and that unstable patients are not studied in the mobile laboratory.

Procedural complications following diagnostic coronary angiography are related to the operator's experience and the catheter size

Cardiac catheterization is performed routinely in hospitals all around the world. Extensive analysis of complications has been performed in the 1980s and early 1990s. However, because of the new therapeutic innovations based on advanced catheter technologies, these data may not apply to the present situation. Still, there are few data about procedural complications of diagnostic cardiac catheterization over the last 10 years. A total of 7,412 consecutive diagnostic cardiac catheterizations were performed between January 1990 and December 2000 and prospectively assessed in a registry. There were a total of 63 complications, of which 40 were minor and 23 major. Thus, the overall complication rate was 0.8%, with a mortality rate of 0%. Univariate analysis showed lower overall complication rate of senior physicians (> 500 coronary angiographies performed; OR = 0.58; 95% CI = 0.34-0.98; P = 0.04), smaller catheter size (< 6, 6, > 6 Fr: OR = 2.6; 95% CI = 1.53-4.41; P = 0.0004), and a higher rate in patients having left and right heart catheterization (OR = 2.62; 95% CI = 1.46-4.7; P = 0.003). Major complications were associated with larger catheters (< 6, 6, > 6 Fr: OR = 2.35; 95% CI = 1.0-5.51; P = 0.05), whereas vascular complications occurred more often with higher body weight (per 10 kg: OR = 1.4; 95% CI = 1.01-1.95; P = 0.04). Overall complication rate in diagnostic coronary angiography is very low and related to the experience of the performing cardiologist and catheter size. The only predicting risk factors for major complications in coronary angiography were catheter size and body weight.

Outpatient coronary angiography: indications, safety, and complication rates

In the years since the introduction of outpatient cardiac catheterization and coronary angiography, the indications for the use of these procedures have expanded rapidly with advancements in surgical and endovascular procedures. The safety of outpatient coronary angiography has been well established, comparing very favorably with that of inpatient procedures. At present, a variety of different outpatient facilities exist. Catheterization laboratories may adjoin a hospital or be free-standing; the safety and success of procedures performed in mobile cardiac catheterization laboratories has also been described. There are a variety of access techniques for cardiac catheterization in use today, and there are many types and sizes of catheters available. Miniaturization of equipment has reduced complications and allowed early ambulation and discharge from outpatient laboratories. In addition, the development and refinement of catheters and techniques for achieving hemostasis may allow further reductions in patient stay and complications. The complication rates of outpatient cardiac catheterization and coronary angiography are, in fact, quite low--in some cases, lower complication rates are seen in the outpatient population than in the inpatient population. Although this is certainly related in part to the fact that outpatients generally have more stable disease, it is clear that careful equipment choices, proper technique, and adequate monitoring have contributed to the success of these important outpatient procedures.

Outpatient cardiac catheterisation

Cardiac catheterisation is increasingly performed in an outpatient setting. The majority of series of outpatient cardiac catheterisation are in laboratories with immediate access to cardiovascular surgery. However, some units may be sited more distantly, although still generally close to a hospital. Compared to an inpatient procedure, outpatient cardiac catheterisation increases bed availability and there are considerable financial rewards with suggested savings of 11-54% of inpatient costs. Most patients are satisfied with an outpatient procedure and, although a quarter may have unanswered questions afterwards, this level may not differ from that found with inpatients. No study has been large enough to detect differences in the major complication rate which occur infrequently in whichever setting, and there is considerable variation between studies in the incidence of minor complications after outpatient procedures. In the only study which randomised all eligible patients to an inpatient (189 patients) or outpatient (192 patients) procedure, seven outpatients (3.6%) suffered bleeding or developed haematomas at the site of percutaneous femoral artery puncture towards the end of the mobilisation period and one patient was syncopal. These events were thought to be a direct result of the procedure being carried out in the outpatient setting. The proportion of patients considered eligible for outpatient cardiac catheterisation varies widely between different series from 20% to more than 80%. Whereas some of this variation may result from the implementation of different exclusion criteria for patients with potentially severe disease, the differences are so large that it is likely that different populations were studied. Unplanned admission rates varied from less than 1% to nearly 19%. With the currently available data no absolute guidelines can be derived to exclude all patients at risk of complications, but the American College of Cardiology/American Heart Association (ACC/AHA) task force recently published guidelines which identified low risk patients suitable for outpatient procedures. These guidelines have been used to select patients for investigation in two mobile units in the USA, and only 0.9% required urgent transfer for clinical instability, and 0.6% developed major complications. However, most patients did not need referral to a tertiary centre for additional procedures and there may be less scope for selecting patients within the ACC/AHA guidelines in the UK compared with the USA.