American Heart Journal
Volume 143, Issue 5 , Pages 745-747, May 2002

Is more better?☆☆☆

New York, NY, and Durham, NC

From the aZena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Medical Center, New York, NY, and the bDuke Clinical Research Institute, Durham, NC

Received 9 November 2001; accepted 27 November 2001.

Article Outline

Abstract 

Am Heart J 2002;143:745-7.

 

See related article on page 833.

All things will be produced in superior quantity and quality, and with greater ease, when each man works at a single occupation, in accordance with his natural gifts, and at the right moment, without meddling with anything else.

—Plato (427-347 bce), Socrates, in The Republic, book 2, section 370

It is quality rather than quantity that matters.

—Lucius Annaeus Seneca (4 bce-65 ce), Epistles

Extensive analyses conducted by Hal Luft more than 2 decades ago are appropriately recognized as some of the earliest work establishing a relationship between procedural experience and outcome.1 The intuitively appealing notion that “practice makes perfect” is, as the first quote suggests, an ancient one, and studies have repeatedly documented better percutaneous coronary intervention (PCI) outcomes with higher operator and laboratory volume.2, 3, 4, 5, 6, 7, 8 The conclusion that a minimum number of procedures per year are necessary to achieve and maintain technical proficiency at both the operator and laboratory level is embodied in the American College of Cardiology/American Heart Association (ACC/AHA) practice guidelines for PCI.5

In this issue of the Journal, Kimmel et al examine angioplasty volume standards from a new perspective.9 To date, the majority of work in this field has concentrated on short-term outcomes, namely, inhospital and 30-day complications and mortality. In a study of 25,222 patients undergoing angioplasty in Pennsylvania between 1994 and 1995, Kimmel considers the relationship between hospital volume and 6-month events. Although lower-volume hospitals (<400 cases/year) were found to have higher rates of bypass surgery before discharge, no such relationship was seen for low-volume hospitals at 6 months. Examining an array of outcomes including repeat angioplasty, bypass surgery, hospitalization for myocardial infarction, and death, the only significant finding at 6 months was a higher rate of myocardial infarction hospitalization for patients treated at the highest-volume (>900 cases per year) hospitals. These data are the first to suggest that the inverse relationship between hospital volume and adverse outcomes is not clinically important at 6 months.

This work runs counter to a series of studies spanning the last decade that repeatedly found worse short-term outcomes for patients treated at low-volume hospitals.2, 3, 4, 5, 6, 7, 8 Such a negative finding raises 2 questions. Are the findings valid and, if so, should volume standards be dropped from current practice guidelines? Regarding the former question, this study was most likely of sufficient size and analytical rigor to identify an association between low-volume and 6-month outcomes in Pennsylvania during the time period. As with many angioplasty studies, questions will remain whether experience in the 1994 to 1995 time period with a 24% stent rate can be generalized to current practice involving approximately 80% stent use.10 Increased stent use has been associated with lower rates of abrupt closure and early surgery and lower rates of restenosis.7, 11, 12 Therefore, differences in these outcomes would be less apparent in more recent data. Ho13 examined trends in PCI outcomes over time in California. She found improvement in outcomes for all providers and a progressive attenuation of the volume-outcome effect between the mid 1980s and the mid 1990s.

Another consideration involves volume-related differences in the deployment of coronary stents. In the Pennsylvania study, hospitals at either end of the volume extreme (<400 and >900 cases/year) had the lowest rate of stenting (19% and 22%, respectively), and stenting rates were sufficiently low that one would not expect an attenuation of subsequent angioplasty or surgery at 6 months. In more recent data from McGrath involving Medicare angioplasty in 1997, the use of stents increased with both hospital volume (low-volume stent rate 48%, high-volume stent rate 59%) and physician volume (low-volume stent rate 51%, high-volume stent rate 61%). If such a differential persists in current practice, it is possible that volume-related use of coronary stents could lead to differences in 6-month repeat procedure rates.

Among the comparisons of 6-month outcomes, another notable finding running counter to the volume-outcome relationship was a significantly higher 6-month myocardial infarction rate among patients treated at the highest volume hospitals. In this study, myocardial infarction was defined according to hospital claims for readmission to a Pennsylvania hospital. Although a reliance on hospital claims to identify myocardial infarction may not be ideal, the 3% to 4% rate is only slightly lower than that seen in clinical trials that rely on more systematic measures.14, 15

Possible explanations include worse secondary prevention at high-volume hospitals, better health care access for patients treated at high-volume hospitals so that they were more likely to be hospitalized in follow-up, or a chance finding. These findings suggest that the possibility of worse 6-month outcomes among very-high-volume hospitals should be considered in other data.

This one study regarding volume and 6-month angioplasty outcomes does not negate the significance of the numerous studies that have repeatedly identified worse short-term outcomes for low-volume hospitals. The consistency of this finding supports volume standards as one element of systems designed to identify quality care for patients undergoing angioplasty. Yet, no matter how strong the association between volume and either short- or long-term outcomes is determined to be, this avenue of quality assessment is fundamentally limited. Limited first because volume implies better outcomes on average but does not necessarily confirm the quality of a particular operator or laboratory. The volume-outcome relationship is limited in its applicability as well. Other than achieving certain volume targets, there are no other processes of care associated with this measure that can be implemented by other providers to improve patient outcomes. The limitations of this approach indicate that we must continue to expand our efforts to specify and measure angioplasty quality.16 Simply stated, assessing “quality” involves the specification of a level of excellence.

To move beyond current approaches to assessing health care quality in general and angioplasty quality in particular, fundamental changes need to occur. First, quality of care needs to become a central component in the calculation of payment. Such a change will direct the powerful engine of market forces to improve care. This change will also lead to adequate resources to enable the second fundamental change, the systematic measurement and collection of adequate data by which to identify, measure, and improve quality. There are currently a large number of private and government initiatives to more effectively measure quality and to link payment to quality including the Pennsylvania Cost Containment Council, the Centers for Medicare and Medicaid Services and National Quality Forum Hospital Core Performance Measure Set, the Pacific Business Group on Health Negotiating Alliance, the Business Roundtable Leapfrog Group, the Joint Commission on Accreditation of Healthcare Organizations Hospital Core Measures, and the American College of Cardiology National Cardiovascular Data Registry. Despite these pioneering efforts, our health system remains focused on cost minimization, and health care providers, government agencies, insurers, and the press primarily rely on claims data to consider quality and outcomes regarding cardiovascular procedures.

Even if financial incentives and information systems can be aligned, quality assessment of PCI could be improved further by an expansion of current quality measures. These should include additional patient-centered metrics such as relief of symptoms, education regarding coronary disease and indications for procedures, and patient satisfaction. Use of such patient-centered outcome measures could make it easier to assess low-volume operators because every patient, not just those who have infrequent adverse events, achieves some measurable end point. Although a patient's perception of his experience may not accurately reflect the technical proficiency of the operator, it is another important dimension of the care provided.

Process measures should also be expanded to include an assessment of the indications for the procedure, laboratory participation in regional quality assessment efforts, time to reperfusion for primary PCI in myocardial infarction, the thoroughness of secondary prevention of coronary heart disease, and additional short- and long-term outcomes. To truly assess quality in a real-time fashion and efficient manner, data collection must be integrated into routine patient care activities, including the preprocedure medical encounters (history and physical examination, informed consent process), scheduling, report generation, laboratory reporting, billing, and follow-up medical encounters. Data collection should focus on the traditional factors that lead to the outcomes of interest, as well as potentially confounding factors that lead to treatment selection. Given the relative low rates of adverse events associated with angioplasty, the expansion of outcome measures to include bleeding or vascular access complications will also better allow for the assessment of individual providers despite “small numbers.” Assessment of additional outcomes such as bleeding complications will also allow for the consideration of potential complications from newer, more aggressive anticoagulant protocols, which are being adopted to avoid the ischemic outcomes that are already being measured.

Returning to the choice between quantity and quality raised by Kimmel's work, higher PCI volume appears to be associated with better short-term outcomes. Additional studies are warranted to consider longer-term outcomes, and to consider the possibility that 6-month outcomes are worse for the highest-volume hospitals. Regarding efforts to assure the highest possible level of angioplasty care, further improvements in quality greatly depend upon the quantity of resources directed to the collection of better information and to enhancements in processes of care. These improvements are likely to occur only when compensation is linked to quality and when quality can be identified as a part of routine care.

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References 

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  2. Jollis JG, Peterson ED, DeLong ER, et al.  The relation between the volume of coronary angioplasty procedures at hospitals treating Medicare beneficiaries and short-term mortality. In: N Engl J Med. 331:1994;p. 1625–1629
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☆ Reprint requests: Ira S. Nash, MD, Zena and Michael A. Wiener Cardiovascular Institute, Mt Sinai Medical Center, Box 1030, 1 Gustave L. Levy Place, New York, NY 10029.

☆☆ E-mail: ira.nash@msnyuhealth.org

PII: S0002-8703(02)22093-1

doi:10.1067/mhj.2002.122117

Refers to article:

  • Relationship between coronary angioplasty laboratory volume and outcomes after hospital discharge

    Stephen E. Kimmel, William H. Sauer, Colleen Brensinger, John Hirshfeld, Howard L. Haber, A.Russell Localio
    American Heart Journal May 2002 (Vol. 143, Issue 5, Pages 833-840)

American Heart Journal
Volume 143, Issue 5 , Pages 745-747, May 2002

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