Timing of Catheterization Post Cabg Surgery : ( Tic-Postcabg )

C l i n M e d International Library Citation: Hayat N, Al Saddah J, Al Mutairi M, Almelahi MA, Remya PRS (2017) Timing of Catheterization Post Cabg Surgery: (Tic-Postcabg). Int J Clin Cardiol 4:088 Received: August 17, 2016: Accepted: January 17, 2017: Published: January 20, 2017 Copyright: © 2017 Hayat N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hayat et al. Int J Clin Cardiol 2017, 4:088


Introduction
Patients with coronary artery bypass grafting (CABG) may redevelop ischemia that necessitates coronary angiography.In addition to native coronary arteries, bypass conduits have to be entered and injected selectively with contrast dye.Either graft failure or native coronary artery disease or both may be the cause of ischemia.There have been many studies that investigate issues related to this topic [1,2].Smokers who go back to smoking, diabetics with poor control or patients with other risk factors may be candidates for recurrent angina [3].What we did not come across is whether timing of angiography (sooner or later after CABG) would identify special group of patients.
During routine catheterization of post CABG patients, they could be divided into 2 groups.Those who had their surgery 5 years or less (group A) and those who had their surgery performed longer than 5 years (group B).In addition to comparing presence of risk factors in both groups, we looked at markers of atherosclerosis, post operative medications and vascular anastomosis within each group.The patients were operated locally or otherwise in City Hospital, Paris or Cleveland Clinic, U.S.A. Thus local results of CABG were compared to those of centers abroad.Thirdly, we wanted to compare new native vessel disease (i.e.not involved in their original CABG) or graft failure in groups A and B and their management.radial grafts for group A that constituted more recently operated patients.The arterial grafts were 40.4% of the total grafts in this group.A random sample of cath reports pre CABG showed no difference in presence of chronic total occlusion among both groups.Similarly degree of calcification and complexity of lesions were nearly identical, i.e. patients who are referred to surgery have complex disease not amenable to PCI.Table 1d describes the different medications and their percentages in both groups.ACE inhibitors were used more in group A patients and Angiotensin Receptor Blockers were used more in group B (both almost approaching statistical significance).
Table 2 describes the percentage of diseased vs. non-diseased conduits used at catheterization.In particular it points to the location of diseased segments of SVG's.The only parameter that shows statistical significance is distal anastomotic junction of the SVG to native vessel.
Table 3 shows the treatment strategy used for the patients in both groups.Medical treatment or PCI to native vessels or graft conduits are given as percentages.In general diffusely diseases vessels and failed grafts were prescribed medical treatment.The other categories are self explanatory.Nine of 33 patients in group A and 27 out of 59 patients in group B were operated abroad.Within group A, fewer patients were referred for catheterization after CABG.

Discussion
This communiqué reports on 92 patients who were referred for catheterization post CABG.The reason for cath was different manifestations of ischemia: Unstable angina, with or without myocardial infarction or heart failure occurred in over in over 95%.
The average age of the full cohort was 62.5 ± 9.5 years with 76 males (82.6%).The patients in group A were 33 and did not differ from group B visa-a-vis, age (mean 60.1 years and 63.8 years respectively).Males predominate with 78.8% in group A vs. 84.7% in group B. The mean number of months at cath time post CABG was 34.2 months for group A vs. 154.6 for group B.
Among classical risk factors (Table 1a), group A had more smokers than group B. The most common reason for catheterization was severe angina (Table 1b).Angina class III and IV was present in 93.9% group A and 84.7% group B. Heart failure occurred in 24.2% and 28.8% for group A and group B respectively.The mean left ventricular ejection fraction was above 50% in both groups.Myocardial infarction occurred at higher percentage for group A compared to group B almost reaching statistical significance.Percentage of PCI before CABG was 18.2% and 13.6% respectively for groups A & B. Post CABG, the PCI percentage increased to 36.4% (group A) and 32.2% (group B).These percentages did not achieve significant difference.Markers of atherosclerosis or factors promoting as such are also tabulated (Table 1a).
Table 1c details the number and type of grafts done for each patient.37 mammary grafts were put in for 33 patients as well as 3   re-CABG as effective treatment for recurrence of ischemia [15,16].In the era of proliferation of PCI, this trend continues to increase for post CABG.We may see more patients developing recurrence of ischemia and thus requiring re-cath.In our series, very few patients go to re-CABG.The choice between medical treatment and PCI is extensive calcification and/or chronic total occlusion, which favors medical treatment.

Conclusion
A significant number of patients redevelop ischemia early (< 5 years) post CABG.Risk factor analysis did not detect differences in early vs. late presentation with ischemia.It seems that those who went for CABG abroad were less likely to come for recatheterization.Operating on diffuse or very complex disease would lead to recurrence of ischemia early.The challenge is to select cases with good targets to minimize early recurrence of ischemia.Finally, in managing these post-CABG patients, only few are referred for re-CABG.The majority either did PCI or was kept on medical treatment.
Ischemia post CABG is rather frequent (as early as one year postinterval) [1,4] and re-intervention is common [4,5].However the percentage of symptomatic recurrence was reported.We noticed that catheterization interval post surgery was variable.Arbitrarily, the patients were divided into 2 groups: Group A had their surgery done in 5 years or less and group B was longer than 5 years.The average number of months post CABG was 34 ± 20 for group A and 154 ± 59 for group B.
At the beginning of recruiting the patients, we hypothesized that patients in group A would have higher percentage of risk factors than their counterparts in group B. This did not pan out (Table 1).Smokers were more frequent in group A, although the difference was not statistically significant.In much larger series, smoking and other risk factors caused recurrence of ischemia in post CABG patients [1].We presume patients with higher risk factor score presented earlier to their treating physician.
The initial CABG surgery was done locally in 60% of the total cohort.In group A, 72.7% of the patients were operated locally.Although the denominator was not known, patients operated abroad came less frequently for catheterization than those operated by local surgeons.Popular centers abroad (one in France and the other in U.S.A) do extensive arterial grafting, especially left internal thoracic artery (LITA) [6][7][8].Using arterial conduits have been shown to delay ischemia recurrence [6,7].Our surgeons have recently started total arterial revascularization.
If risk factors fail to distinguish patients with early vs. late recurrence, then what is the plausible explanation?We checked for factors that promote and/or markers of atherosclerosis, as given in table 1a, and again could not come up with any definite answer.New native vessel disease or graft failure (Table 4) did not discriminate either.Myocardial infarction post CABG was more common in group A. Lesion characteristics (as calcification, bifurcation or total occlusion) were not dissimilar (ascertained from review of 10 randomly selected angios in each group).The only positive discriminator between group A and B is distal anastamotic disease which was more common in group A. There are 2 possible explanations-one is faulty surgical suturing (which is untenable because of different surgeons and centers).The most likely explanation is that PCI proliferation has forced surgeons to accept cases with diffuse disease and poor run off.In the past they were not as likely to accept these cases.
Management of post CABG ischemia has shifted to less re-CABG and more to PCI and medical treatment [4,5] (Table 3).It is reported lower percentage of CABG patients survive or are angina free if they had prior PCI [9][10][11].Others have shown that in head to head comparison, survival benefit for PCI post CABG holds for 3 years over re-CABG [4].Also PCI of native vessels or grafts are simple and safe once the experience has been gained [12,13].In contrast, re-CABG has higher mortality than first [4,14].Old literature praises

Table 1a :
Risk factors in groups A & B.

Table 3 :
Mode of treatment in post CABG patients after catheterization.

Table 4 :
Coronary artery and bypass conduit anatomy in Group A & B.