View source for Chronic stable angina PCI and CABG versus medical therapy

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{{Chronic stable angina}}

{{CMG}}; '''Associate Editor(s)-In-Chief:''' [[Lakshmi Gopalakrishnan, M.B.B.S.]] 

==Overview==
The ''Mass'' and ''Mass-II'' trials directly compared the effect of [[Chronic stable angina pharmacotherapy overview|medical therapy]], [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] and [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] for the management of chronic stable angina.<ref name="pmid7594092">Hueb WA, Bellotti G, de Oliveira SA, Arie S, de Albuquerque CP, Jatene AD et al. (1995) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=7594092 The Medicine, Angioplasty or Surgery Study (MASS): a prospective, randomized trial of medical therapy, balloon angioplasty or bypass surgery for single proximal left anterior descending artery stenoses.] ''J Am Coll Cardiol'' 26 (7):1600-5. [http://dx.doi.org/10.1016/0735-1097(95)00384-3 DOI:10.1016/0735-1097(95)00384-3] PMID: [http://pubmed.gov/7594092 7594092]</ref><ref name="pmid15145093">Hueb W, Soares PR, Gersh BJ, César LA, Luz PL, Puig LB et al. (2004) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=15145093 The medicine, angioplasty, or surgery study (MASS-II): a randomized, controlled clinical trial of three therapeutic strategies for multivessel coronary artery disease: one-year results.] ''J Am Coll Cardiol'' 43 (10):1743-51. [http://dx.doi.org/10.1016/j.jacc.2003.08.065 DOI:10.1016/j.jacc.2003.08.065] PMID: [http://pubmed.gov/15145093 15145093]</ref> However, there are a few reservations to the application of results from these studies as they did not include the current optimal strategies of therapy.

==PCI and CABG vs Medical Therapy==
===Limitations===
There are some reservations to the application of results from older randomized trials such as ''Mass'' and ''Mass II'' trials to the current clinical practice as they assessed patients prior to the era of [[Chronic stable angina medical therapy|current optimal medical regimen]], [[Chronic stable angina treatment anti-lipid agents|aggressive lipid-lowering therapy]], [[Chronic stable angina revascularization drug eluting stents|drug-eluting stent]] and [[Chronic stable angina secondary prevention|lifestyle intervention]].

===Clinical Trial Data: The Medicine, Angioplasty or Surgery Study ''(MASS)''<ref name="pmid7594092">Hueb WA, Bellotti G, de Oliveira SA, Arie S, de Albuquerque CP, Jatene AD et al. (1995) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=7594092 The Medicine, Angioplasty or Surgery Study (MASS): a prospective, randomized trial of medical therapy, balloon angioplasty or bypass surgery for single proximal left anterior descending artery stenoses.] ''J Am Coll Cardiol'' 26 (7):1600-5. [http://dx.doi.org/10.1016/0735-1097(95)00384-3 DOI:10.1016/0735-1097(95)00384-3] PMID: [http://pubmed.gov/7594092 7594092]</ref>===

====Study Population====
214 patients with [[Chronic stable angina definition|chronic stable angina]], [[LV function|normal ventricular function]] and a [[stenosis|proximal stenosis]] of the [[LAD|left anterior descending coronary artery]] greater than 80% were randomized to undergo [[Chronic stable angina revascularization coronary artery bypass grafting|mammary bypass surgery]] (n=70), [[Chronic stable angina revascularization percutaneous coronary intervention|balloon angioplasty]] (n=72) or [[Chronic stable angina medical therapy|medical therapy alone]] (n=72).

====Results: Primary End-point====
The composite primary endpoint of all cause mortality, non-fatal MI or refractory angina requiring [[Chronic stable angina revascularization|revascularization]], during a mean follow-up of 3-years was significantly different among the PCI and CABG groups (P=0.0002) and among the CABG and medical therapy groups (P=0.006) and no significant difference observed between the PCI and medical therapy group (P=0.28): 3% in the [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]], 24% in the [[Chronic stable angina revascularization percutaneous coronary intervention|PCI group]] and 17% in the [[Chronic stable angina medical therapy|medical therapy group]]. However, there was no difference in mortality or [[MI|infarction]] rates among the groups.

====Results: Secondary End-point====
*No patient allocated to bypass surgery needed [[Chronic stable angina revascularization|revascularization]], compared with eight and seven patients assigned, respectively, to PCI and medical therapy (P=0.019). 

*Both revascularization techniques resulted in greater symptomatic relief and a lower incidence of [[ischemia]] on the [[Chronic stable angina risk assessment in patients with an intermediate or high probability of coronary artery disease|treadmill test]]; however, all three strategies eventually resulted in the abolition of limiting angina.

====Conclusion====
The study concluded that for patients with a single severe [[LAD|proximal LAD]] [[stenosis]], a more aggressive therapeutic approach with initial [[Chronic stable angina revascularization coronary artery bypass grafting|bypass surgery]] was associated with a lower incidence of medium-term adverse events than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina pharmacotherapy overview|medical therapy]]. However, all the three strategies resulted in a similar incidence of death and [[MI|infarction]] during an average follow-up period of 3 years.

====''MASS'': 5-year Follow-Up<ref name="pmid10567287">Hueb WA, Soares PR, Almeida De Oliveira S, Ariê S, Cardoso RH, Wajsbrot DB et al. (1999) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=10567287 Five-year follow-op of the medicine, angioplasty, or surgery study (MASS): A prospective, randomized trial of medical therapy, balloon angioplasty, or bypass surgery for single proximal left anterior descending coronary artery stenosis.] ''Circulation'' 100 (19 Suppl):II107-13. PMID: [http://pubmed.gov/10567287 10567287]</ref>====

The primary endpoint defined as the occurrence of [[MI|acute MI]], death or presence of refractory angina requiring [[Chronic stable angina revascularization|revascularization]], during a 5-year follow-up was significantly lower with [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]]  or [[Chronic stable angina medical therapy|medical therapy]] (6 patients versus 29 patients and 17 patients respectively; P=0.001). However, all the three treatment regimens yielded a similar incidence of cardiac-related death (P=0.622). Thus, the study concluded that [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] for single-vessel disease was associated with a lower incidence of medium-term and long-term events as well as fewer anginal symptoms than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina medical therapy|medical therapy]].

===Clinical Trial Data: The Medicine, Angioplasty or Surgery Study ''(MASS-II)''<ref name="pmid15145093">Hueb W, Soares PR, Gersh BJ, César LA, Luz PL, Puig LB et al. (2004) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=15145093 The medicine, angioplasty, or surgery study (MASS-II): a randomized, controlled clinical trial of three therapeutic strategies for multivessel coronary artery disease: one-year results.] ''J Am Coll Cardiol'' 43 (10):1743-51. [http://dx.doi.org/10.1016/j.jacc.2003.08.065 DOI:10.1016/j.jacc.2003.08.065] PMID: [http://pubmed.gov/15145093 15145093]</ref>===

====Study Population====
611 patients with multi-vessel disease (58% had triple-vessel disease and 92% had LAD disease), [[LV function|preserved ventricular function]] and chronic stable angina with [[Canadian cardiovascular society classification of angina pectoris#Canadian Cardiovascular Society Severity Classification (CCS)|CCS class II or III]] were randomized to undergo [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] (n=203), [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] (n=205) or [[Chronic stable angina medical therapy|medical therapy]] alone (n=203).

====Results: Primary End-point====
The incidence of composite primary endpoint of all cause mortality, [[Q wave MI]] or refractory angina requiring [[Chronic stable angina revascularization|revascularization]], during a 1-year follow-up was significantly lower with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] than with [[Chronic stable angina medical therapy|medical therapy]] or [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] (76% versus 88% and 93% respectively). However, the 1-year mortality was significantly lower with the [[Chronic stable angina medical therapy|medical therapy group]] than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] (1.5% versus 4.5% and 4.0% respectively).

====Results: Secondary End-point====
*After one-year follow-up, 8.3% of [[Chronic stable angina medical therapy|medically treated]] patients and 13.3% of [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] patients underwent additional interventions, compared to only 0.5% of [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] patients. 

*At one-year follow-up, 88% of the patients in the [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]], 79% in the [[Chronic stable angina revascularization percutaneous coronary intervention|PCI group]], and 46% in the [[Chronic stable angina medical therapy|medically treated group]] were free of angina (P<0.0001).

====Conclusion====
The study concluded that [[Chronic stable angina medical therapy|medical therapy]] for [[CAD|multi-vessel CAD]] was associated with a lower incidence of short-term events and a reduced need for additional [[Chronic stable angina revascularization|revascularization]], compared with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]]. In addition, [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] was shown to be superior to [[Chronic stable angina medical therapy|medical therapy]] for eliminating anginal symptoms. However, all the three therapeutic regimens yielded relatively low rates of cardiac-related deaths.

====''MASS-II'': 5-year Follow-up<ref name="pmid17339566">Hueb W, Lopes NH, Gersh BJ, Soares P, Machado LA, Jatene FB et al. (2007) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=17339566 Five-year follow-up of the Medicine, Angioplasty, or Surgery Study (MASS II): a randomized controlled clinical trial of 3 therapeutic strategies for multivessel coronary artery disease.] ''Circulation'' 115 (9):1082-9. [http://dx.doi.org/10.1161/CIRCULATIONAHA.106.625475 DOI:10.1161/CIRCULATIONAHA.106.625475] PMID: [http://pubmed.gov/17339566 17339566]</ref>====

*The incidence of composite primary endpoint from all cause of mortality, [[Q wave MI]] or presence of refractory angina requiring [[Chronic stable angina revascularization|revascularization]], during a 5-year follow-up was found to be significantly lower with [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina medical therapy|medical therapy]] (21.2% versus 32.7% and 36% respectively; P=0.0026). However, no statistical difference was observed in the overall mortality among the three groups.

*The pairwise treatment comparisons of the primary end points showed no difference between [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] and [[Chronic stable angina medical therapy|medical therapy]] group (RR 0.93; 95% CI, 0.67 to 1.30) and a significant protective effect of [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] compared with [[Chronic stable angina medical therapy|medical therapy]] (RR, 0.53; 95% CI, 0.36 to 0.77).

*In addition, a significant number of patients who received [[Chronic stable angina medical therapy|medical therapy]] and [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] underwent repeat revascularization procedures compared to the [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] (9.4% versus 11.2% and 3.9% respectively; P=0.0026). Moreover, 15.3%, 11.2%, and 8.3% of patients experienced [[MI|non-fatal myocardial infarction]] in the [[Chronic stable angina medical therapy|medical therapy]], [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]], and [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] groups, respectively (P<0.001). 

*No significant difference in survival was noted among the three groups (88% to 92%).

====''MASS-II'': 10-year Follow-up<ref name="pmid20733102">Hueb W, Lopes N, Gersh BJ, Soares PR, Ribeiro EE, Pereira AC et al. (2010) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=20733102 Ten-year follow-up survival of the Medicine, Angioplasty, or Surgery Study (MASS II): a randomized controlled clinical trial of 3 therapeutic strategies for multivessel coronary artery disease.] ''Circulation'' 122 (10):949-57. [http://dx.doi.org/10.1161/CIRCULATIONAHA.109.911669 DOI:10.1161/CIRCULATIONAHA.109.911669] PMID: [http://pubmed.gov/20733102 20733102]</ref>====

The incidence of primary endpoint, during a 10-year follow-up was significantly higher with [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina medical therapy|medical therapy]] (73% versus 55% versus 49% respectively). Relative to the composite end point, ''Cox regression analysis'' showed a higher incidence of primary events in [[Chronic stable angina medical therapy|medical therapy]] than in [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]] (HR 2.35; 95% CI, 1.78 to 3.11) and in [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] than in CABG (HR 1.85; 95% CI, 1.39 to 2.47).

The 10-year rates of [[myocardial infarction]] was significantly higher with [[Chronic stable angina medical therapy|medical therapy]] than with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] or [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] (20.7% versus 13.3% and 10.3%; P<0.010).

The 10-year rates of additional [[Chronic stable angina revascularization|revascularizations]] was significantly higher with [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] than with [[Chronic stable angina medical therapy|medical therapy]] or [[Chronic stable angina revascularization coronary artery bypass grafting|CABG group]] (41.9% versus 39.4% and 7.4%; P<0.010).

No significant difference in survival among the three groups (69% to 75%).

Thus, the study concluded that in comparison to [[Chronic stable angina revascularization coronary artery bypass grafting|CABG]], [[Chronic stable angina medical therapy|medical therapy]] and [[Chronic stable angina revascularization percutaneous coronary intervention|PCI]] were associated with a significantly higher incidence of subsequent [[myocardial infarction]], a higher rate of additional [[Chronic stable angina revascularization|revascularization]], a higher incidence of cardiac death, and consequently a 2.29-fold increased risk of combined events with medical therapy and a 1.46-fold increased risk with CABG. Additionally, CABG was better than medical therapy at eliminating anginal symptoms.

==References==
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