Internal mammary artery flow in different racial groups of Pakistan.

Objective: To find out any differences in free flow of internal mammary artery among different ethnic groups.
Methods: This observational, cross-sectional study was conducted at the Civil Hospital, Karachi, from January 2013 to December 2015, and comprised patients who underwent coronary artery bypass grafting. The participants were divided into 5 groups, i.e. Sindhi, Muslim migrants from India, Punjabi, Pathan and Balochi patients. Free flow of internal mammary artery was measured immediately after harvesting within a syringe, and its flow was measured in 30 seconds. SPSS 18 was used for data analysis.
Results: Of the 158 patients, 44(27.8%) were Sindhi, 33(20.9%) Punjabi, 8(5%) Baloch, 21(13.3%) Pathan and 52(32.9%) were migrants. The overall mean age was 52±8 years and the mean flow was 11.6±9.6ml per 30 seconds. The flow was 9.3±6 ml, 10±8ml, 13±11ml, 17±14ml and 15±13 ml in 30 seconds among migrants, Sindhi, Punjabi, Pathan and Baloch patients, respectively, with significant higher flow in Pathan patients compared to Sindhi and migrant patients (p<0.05). A flow of less than 5ml/30 sec was mostly found in migrants or Sindhi subjects 30/40(75%), and flow more than 30ml/ 30 seconds was found mostly in Baloch or Pathan patients 4/8(50%). Low flow internal mammary artery, which was used on left anterior descending artery, showed significantly higher need of inotropic support as compared to high flow internal mammary artery (p=0.004), more low cardiac output syndrome (p=0.022) and more use of intra-aortic balloon pump (p=0.028).
Conclusions: Internal mammary artery flow was higher in Pathan and Baloch patients and low in migrants and Sindhis.