Agree that as an ESIR applicant we are looking at the total package 1) letters (most importantly letters from someone we know and trust) 2) IR research 3) procedural and clinical experience (ICU/clinical blocks/procedural experience (diversity and volume and primary operator experience) 4) networking at meetings , virtual lectures etc (arguably most important to showcase your interest and passion for IR ) 5) ACR in service training exam scores 6) Internship (if all of the above are similar may use this as a tiebreaker to see if you were ready to take on the challenge of a busy intern year and thus would be less likely to have problems dealing with a super busy IR fellowship). The internship does not make or break you but a strong surgical internship does give one a lot of confidence, stamina and less fear than the average medicine or TY prelim graduate. I personally feel we need more of the aggressive can do attitude that is more pervasive in surgical disciplines.
Though I have done a reasonable number of ports and feel my suturing is "adequate" and get follow up in clinic to see how the incision has healed and if there are any port issues. I do recognize that my suturing skills are not as refined as I personally would like and I have tried to pick up tips from those who have done surgery so I can improve on that. Ideally I would scrub with a plastic surgeon and really get this aspect down . Most of my sutures are to suture drains in and I feel that I can do that fairly well.
When I was initially working on surgical femoral arterial cutdowns prior to the use of proglide( I struggled with the Castros and the 5-0 polypropylene stitches which even the surgical interns managed much more adeptly). The day to day existence that I personally have reflects a surgical field far more than IM or TY. I round prior to my operating day, I have to do inpatient consults (similar to acute care surgery). We deal with post operative periprocedural complications. (sepsis/bleeding) etc. The surgical residents (on average) develop more stamina and are able to see more patients efficiently.
The surgical rotations are quite helfpful for radiology as well as VIR. It is essentially 12 months of anatomic based training, surgical techniques, improving manual dexterity (simulation lab/ operative time/ minor procedures including I and D at bedside etc). Surgical oncology is comparable to what we need to know (resection and ablation are comparable in goals (curative intent)), staging of cancers (Colorectal cancer, liver cancer (HCC/ cholangiocarcinoma/Neuroendocrine tumor), endocrine (thyroid/parathyroid), thoracic surgery (lung cancer staging, treatment, nodal station anatomy), Acute care surgery (bowel obstruction, cholecystitis, appendicitis, diverticulitis, hernias, pancreatitis), trauma (blunt/ penetrating), transplant (renal, liver, pancreas, small bowel), Breast surgery (mammography, mastectomy, needle localization, axillary node dissection, lumpectomy), cardiac surgery (CABG, Valves (stenosis/regurg/endocarditis), aortic dissections) and the perioperative management including IABP etc, SICU (dealing with postoperative bleeding, infections , anastomotic leaks etc). Not all programs are the same so it is important to identify a surgical internship which will give you adequate time doing floor work (improve efficiency and deal with floor issues), ICU time (deal with ill patients with multi-organ support (dialysis, pressors, ventilators etc), clinic time (seeing new consults and follow up to learn the disease), operative time (to improve your anatomic knowledge and knowledge of surgeries and manual dexterity). The below has some links of some surgical programs.