Letter Regarding Article by Gammie et al, “Influence of Hospital Procedural Volume on Care Process and Mortality for Patients Undergoing Elective Surgery for Mitral Regurgitation”
To the Editor:
We read with interest the article by Gammie et al1 in the February issue of Circulation. The authors elegantly emphasize the known volume-outcome2 effect and inverse relationship between case volume and mortality. One interesting caveat addressed in an editorial in Circulation in 20023 was “what causes the leakage is fundamental to the outcome of valve repair.” The authors were questioning the outcomes of ischemic versus nonischemic mitral valve disease. Furthermore, in a recent meta-analysis4 by etiological classification, there was strong evidence of differences in 30-day and total survival outcomes favoring repair for 3 disease groups (rheumatic, mixed, and degenerative). Surgery for ischemic mitral valve had lower 30-day mortality for repair than replacement, but no statistically significant difference in the overall survival was detected. On the basis of the tenets of etiology and acknowledging the hard work by the authors, we would appreciate finding out whether such a volume-effect outcome existed for the different mitral valve disease states.
Gammie JS, O’Brien SM, Griffith BP, Ferguson TB, Peterson ED. Influence of hospital procedural volume on care process and mortality for patients undergoing elective surgery for mitral regurgitation. Circulation. 2007; 115: 881–887.
Urbach DR, Baxter NN. Does it matter what a hospital is “high volume” for? Specificity of hospital volume-outcome associations for surgical procedures: analysis of administrative data. BMJ. 2004; 328: 737–740.
Enriquez-Sarano M, Schaff HV, Frye RL. Mitral regurgitation: what causes the leakage is fundamental to the outcome of valve repair. Circulation. 2003; 108: 253–256.
Shuhaiber J, Anderson RJ. Meta-analysis of clinical outcomes following surgical mitral valve repair or replacement. Eur J Cardiothorac Surg. 2007; 31: 267–275.