Which cardiothoracic surgery training pathway is right for you?

Abstract

Objective

The training pathways in cardiothoracic surgery have evolved so that there are currently several viable options to this career. The purpose of this review is to give insight to medical students and mentors regarding the 4 different pathways.

Methods

The evolution of cardiothoracic surgery training and 4 current pathways are briefly reviewed. The main differences between these 4 pathways are then discussed in detail.

Results

Key differences between training pathways include time to completion, opportunities for dedicated academic development or research time, family planning considerations, board certification options, opportunities to change programs, competitiveness, and unique considerations for military personnel.

Conclusions

This detailed comparison of the training pathways can serve as a resource to help students make informed decisions about the pathway that is best suited to each individual.

Pathways to cardiothoracic surgery.

Central Message.

There are multiple pathways to becoming a successful cardiothoracic surgeon. Understanding key differences in the different pathways is helpful for trainees and their mentors.

Perspective.

The pathways to cardiothoracic surgery training in the United States have evolved over recent decades and now include the traditional, integrated, 4 + 3, and vascular surgery pathways. Key differences include clinical time to completion, breadth of training, and competitiveness. Each of these pathways can lead to a successful, rewarding career in cardiothoracic surgery.

The first thoracic surgery training program was formed by John Alexander in 1928 and was based on a 2-year fellowship that followed general surgical training.¹ Thoracic training at that time focused almost completely on noncardiac structures. During the 1950s, surgery on the heart and great vessels became more feasible with the advent of the cardiopulmonary bypass machine. Cardiac surgeons in the 1950s were also trained in general surgery, and many subspecialized without further formal fellowship training. Requirements for specialization in thoracic surgery became more standardized in the 1970s.² Between the time of the development of standard criteria and the introduction of accelerated pathways in 2008, the primary way to become a board-certified cardiothoracic surgeon was to complete a general surgery residency followed by a cardiothoracic surgery fellowship.

Before the introduction of the modern accelerated programs that in 2008, there were 2 lesser-known integrated thoracic programs in the 1990s and early 2000s: Duke University School of Medicine and Johns Hopkins University School of Medicine. Hopkins’ program recruited medical students to a 9-year program that led to both American Board of Surgery (ABS) and American Board of Thoracic Surgery (ABTS) certification. These programs included a unique structure: Residents spent the 2 years in general surgery followed by 2 years of cardiothoracic research followed by 2 additional years in general surgery. After these 6 years, residents spent 3 years in cardiothoracic surgery training, which included cardiac, thoracic, and elective rotations. Although these 2 programs were successful by many metrics (passage of both sets of board exams, excellent job placement, subsequent leadership positions within institutions and organizations, and low attrition rate), the ABS determined that it was necessary to have 5 clinical years of general surgery, which resulted in the final 2 integrated residents starting the program in 2009 (W. Baumgartner, MD, personal communication, November 4, 2024).

Although those early integrated programs did not last, modern integrated programs with different structures were introduced in 2008 and have grown steadily throughout the country, with 48 positions offered in 2024.³ The most common training pathway is still the traditional general surgery pathway, with 92 positions available in 2024.³ Medical students who are interested in cardiothoracic surgery now have the opportunity and challenge of deciding which pathway is best for them. In this article, we describe each option and review the pros and cons of each.

Current Pathways

There are now 4 routes to becoming a board-certified cardiothoracic surgeon.^4,5 The traditional pathway involves completion of a 5-year general surgery residency (often with 1-3 additional years for academic development [AD] or research) followed by a 2- or 3-year traditional cardiothoracic surgery fellowship. In 2008, the first accelerated pathways were introduced. The most common accelerated pathway is a 6-year integrated residency (I-6), in which residents obtain some general surgery training and spend most rotations on cardiac and thoracic rotations. The less common accelerated pathway is a 4 + 3 model in which residents complete 4 years of general surgery followed by 3 years of specialty training in cardiothoracic surgery.⁶ In 4 + 3 programs, 6 months is spent in cardiothoracic surgery rotations during each of the fourth and fifth years of general surgery training, followed by 2 years of dedicated traditional cardiothoracic surgery training. The newest option is a 5-year residency in vascular surgery followed by a 2- or 3-year traditional fellowship in cardiothoracic surgery.⁴ Superfellowships, which provide additional concentrated training in a subspecialty—such as congenital, thoracic transplantation, or aortic surgery—can follow any of these training pathways.

The 4 + 3 pathway is the least common pathway and often the least familiar to medical students. There is also variability in how a trainee enters 1 of these programs, which causes confusion for prospective applicants. According to the Accreditation Council for Graduate Medical Education (ACGME), a trainee can apply to enter a 4 + 3 program as a medical student when applying for residency or after entering residency (before postgraduate year 3).⁷ This pathway combines several of the strengths of both the traditional and the integrated programs,⁶ as discussed below. For residents who are interested in the 4 + 3 pathway, it can be helpful to identify such programs during medical school, even if a student is planning to only apply to general surgery but has an interest in cardiothoracic. If a student's interest in cardiothoracic surgery grows early in residency, it may be ideal to enter the 4 + 3 program at that same institution.

Each of the training pathways has produced competent surgeons in both cardiac and thoracic surgery.⁸ So far, no data have shown that 1 is universally better than the other in terms of quality of training. Some stakeholders favor the traditional pathway,⁹ whereas others favor the newer accelerated pathways.¹⁰ Notable factors that are different between the programs are the time to completion, eligibility for general surgery board certification, breadth versus depth of education early in training, level of flexibility to change subspecialties during training, and competitiveness (Table 1). Some elements that may be different between pathways, but for which published data are lacking, include differences regarding attrition rates,¹¹ board exam pass rates, likelihood of taking time for AD during residency, or likelihood of entering a superfellowship.

Table 1.

Differences in the each of the 4 pathways to cardiothoracic surgery^∗

Factor	Traditional	I-6	4 + 3	Vascular
Clinical time to completion	7-8 y	6 y	7 y	7-8 y
General surgery board eligible	Yes	No	Yes	No
Early training focus	General	Cardiothoracic	General	Vascular
Abdominal surgery exposure	Extensive	Limited	Extensive	Variable
General surgery case requirements	250 ABS core by start of PGY3	150 ABS core + 125 cardiothoracic cases + 100 any (total 375 cases) by start of PGY4	250 ABS core by start of PGY3	No ABS core minimums, but 24 mo of general surgery rotations over 5 y required
Flexibility to change specialty†	More	Less	More	Less

I-6, Integrated pathway; ABS, American Board of Surgery; PGY, postgraduate year.

^∗This table represents abbreviated and generalized differences between the major pathways to cardiothoracic surgery and does not include time spent for academic development. ABS core refers to a list of cases that are considered essential components of training in general surgery.

^†Flexibility to change specialties is variable and switching between different residency programs (eg, I-6 to general surgery or general surgery to vascular) during the early years is often possible with approval by the Accreditation Council for Graduate Medical Education.

Comparing the Pathways

One difference between pathways is the clinical time to completion, and this is often a deciding factor for medical students who want to become independent surgeons in what can be or is perceived to be a shorter amount of time. The traditional pathway takes a minimum of 7 years of clinical work after medical school (assuming a 5-year general surgery program followed by a 2-year cardiothoracic surgery fellowship) and up to 10 years (assuming 5 years of clinical general surgery with 2 years of AD followed by a 3-year cardiothoracic surgery fellowship). The integrated pathway takes a minimum of 6 years of focused training in cardiothoracic surgery and up to 8 years (if 2 years of AD). The 4 + 3 model takes at least 7 years and up to 9 years (if 2 years of AD). The vascular surgery model takes a minimum of 7 years (5 years vascular with 2 years of traditional cardiothoracic) and a maximum of 10 years with 5 years of vascular with 2 AD years, and 3 years of traditional cardiothoracic (Figure 1). Students should be aware that these numbers vary even further than the ranges stated here. Years taken for AD during residency can vary from 0 to 3. Some traditional fellowship programs are 2 years, whereas others are 3 years. Some residents take 1 or more years of superfellowship training after the completion of the training required for board certification. Finally, other unforeseen factors can expand time in residency, such as taking a preliminary surgical internship before a categorical internship or taking a leave of absence during training.

Figure 1.

Comparison of duration of training pathways. The traditional and vascular pathways each involve 5 years of residency, 2 to 3 years of fellowship, and 0 to 2 academic development (AD) years (often called research time). The integrated (I-6) pathway involves 6 residency years and 0 to 2 AD years. The 4 + 3 pathway involves 4 years of general surgery, 3 years of cardiothoracic surgery, and 0 to 2 AD years. All pathways allow the option of superfellowships after other training is completed. Of note, other minor variations on this pathway exist that are not shown (eg, trainees may take 3 years of AD and superfellowships can be extended beyond 1 year).

As noted, taking 1 to 3 years off from clinical work for AD affects the time to completion of training. Programs traditionally referred to AD time as research years, and many still do. However, referring to it as AD time is more inclusive because many trainees have productive nonclinical time by focusing on nonresearch activities. Many general surgery programs offer residents the chance to take these years after postgraduate year 2 or postgraduate year 3. Some academic programs require this experience. Years for AD are less common in accelerated programs, although they are becoming more common and even required at some programs, as well. Although this focused AD time adds to the total time of training, it allows residents to network, gain important research and clinical skills, or obtain additional education. These years can be particularly influential for surgeons who will enter academic practice.³

Differences in time to completion and AD years may influence students who are interested in planning for pregnancy, spousal or parental commitments, or other family needs. Residents or their partners can successfully navigate pregnancy and parenthood at any point in training. The ACGME requires that all programs allow for a personal leave of at least 6 weeks, which includes parental leave.¹² The ABTS also has a policy regarding trainee leave that is in line with the ACGME.¹³ Specific policies vary by individual program (eg, many allow more than 6 weeks), so students should inquire about this when applying in addition to being familiar with the policies of governing bodies. If a trainee desires to avoid having children during clinical rotations, he or she has 3 options. One, he/she can enter a program that allows AD years (which can be in any pathway) with plans to become pregnant during that time. Two, he/she can enter a traditional or vascular program and plan for pregnancy between residency and cardiothoracic surgery fellowship. Three, he/she can plan for pregnancy after training. Of course, such planning is challenging because pregnancy and other life events do not always occur on schedule and may be met with unplanned complications.¹⁴ Students can be encouraged that the field of cardiothoracic surgery acknowledges the needs of trainees and their families and is working toward creating programs that foster a supportive environment, although there is still work to be done.^15,16

In the traditional pathway and the 4 + 3 model, surgeons become board-eligible for both general surgery (ABS) and cardiothoracic surgery (ABTS) at the completion of training. Traditionally, to obtain board certification in thoracic surgery, not only was completion of a general surgery residency necessary, but also certification by the ABS was required to be able to sit for the written and oral board exams by the ABTS. This is no longer the case. In the integrated pathway, trainees do not rotate on all general surgery services or obtain appropriate cases and case numbers needed for ABS certification during residency, and therefore, they are only eligible for ABTS certification at the completion of training. The possibility of dual board certification offers theoretical protection from future unemployment, allows for returning to general surgery if there is a change in career interest, and demonstrates expertise in procedures involving the abdomen. Proficiency in abdominal surgery is important for thoracic surgeons who perform benign and malignant procedures on the esophagus or diaphragm and for those surgeons who aspire to be department of surgery chairs who wish to remain relevant in the field. Some surgeons also suggest that the level of responsibility and experience of running a service as a chief resident in these pathways is extremely valuable.

The breadth of training is widest in the traditional pathway. Five years of training in general surgery includes acute care, trauma, vascular, surgical oncology, colorectal, thoracic, pediatric, and critical care. This breadth has the clinical upside of allowing future cardiac surgeons increased ability to recognize general surgery emergencies (eg, bowel ischemia) and increased comfort with facilitating management of such issues. The merits of general surgical services provide important educational and training opportunities for future cardiothoracic surgeons that are not necessarily included in integrated programs. Many cardiothoracic surgeons note that this broad exposure fosters development of invaluable nontechnical skills such as leadership, communication, teamwork, and problem-solving. In general, it is a more well-rounded surgical experience, similar to the training experience of many years ago.

When comparing the training experiences of junior residents during the first years of the different training pathways, integrated programs offer the most focused time spent on cardiac and thoracic services. This early exposure allows earlier acquisition of specialty-specific skills, including echocardiography, coronary angiography, interventional cardiology procedures, and vascular anastomoses. Providing this training to junior residents requires investment and institutional buy-in, but many programs have made changes to facilitate this. For example, many hospitals have moved away from traditional silos of departments of surgery in favor of heart and vascular institutes/centers, in part to better support integrated training programs. The specialized focus on cardiac and thoracic in I-6 does mean that there is less exposure to other surgical specialties like acute care surgery that are useful in the care of critically ill patients. The focus of training becomes increasingly similar during the later stages of all pathways.

Opportunities to change residency programs are different for each pathway. Residents may be able to leave a general surgery program and transfer into an I-6 program and vice versa with ACGME approval. This usually happens within the first 3 years. Open positions for each specialty are often posted by the Association of Program Directors in Surgery or by the Thoracic Surgery Directors Association.^17,18 Of course, general surgery residents who are interested in thoracic surgery when starting an intern year can change their minds (eg, to vascular or trauma surgery) without switching residencies. Residents in I-6 programs who change their minds from cardiothoracic surgery must transfer programs. Many medical students are interested in cardiothoracic surgery but are not completely sure that it’s their preferred specialty. For those students, especially if their exposure to the field is limited, the traditional pathway offers valuable exposure to a variety of specialties with the opportunity to still pursue a career in cardiothoracic surgery. Unfortunately, general surgery residents often have limited exposure to cardiac surgery, and many will never see cardiac surgery during training unless they specifically seek the exposure. For students who are certain about cardiothoracic surgery from the time they are in medical school, an accelerated residency may be appropriate.

Moving programs during training can happen with any pathway, such as transitioning from residency to fellowship or transferring during residency (eg, general surgery to I-6). This is viewed differently by individual trainees. Moving to a different hospital and/or to a different city can be stressful and expensive. For example, trainees who have children often develop a support system and routines in the city where their residency is. Additionally, some trainees simply prefer to complete training with attendings and mentors with whom they have gained familiarity and developed relationships. Alternatively, moving can be an exciting opportunity to expand one's network and gain diverse experiences in varying hospital systems and departments. Learning from different surgeons in new environments can be stimulating, and some trainees may appreciate that fresh start.

The competitiveness of different training programs is also a consideration. In 2025, all pathways to cardiothoracic surgery are competitive. Shumway said the hardest thing about cardiac surgery was getting the chance to do it,¹⁹ and an element of that still rings true. The match rates for the traditional fellowship from 2021 to 2024 were between 56% and 59%, and recent data suggest that only 40% match into 1 of their top choices.²⁰ Match rates for integrated residencies have been even more daunting, ranging from 36% to 42% between 2021 to 2024.³ For medical students who don't have a highly competitive application, planning for the traditional pathway may be best. Students who apply to an I-6 program and don't match often still pursue cardiothoracic surgery training via another pathway.²¹ Mentors in cardiothoracic surgery can be instrumental by having an honest discussion with an applicant about his/her competitiveness and providing personalized advice.

Trainees who plan to pursue the traditional pathway need to consider that some fellowship programs have specific subspecialty tracks for thoracic and cardiac, whereas other fellowships do not have subspecialty tracks, and instead offer broad training in cardiac, thoracic, and congenital cardiac. The ABTS outlines case requirements for trainees completing any of the tracks within a fellowship.²² For example, cardiothoracic surgery fellows in the combined, thoracic, and cardiac tracks are required to complete 60, 30, and 90 surgeries treating valvular heart disease, respectively, to meet requirements for that track.²² These tracks allow trainees who already have a subspecialty in mind when starting fellowship to focus more of their time on specific cases that they will perform in practice. However, trainees who are unsure if either cardiac or thoracic is right for them may want to choose a program with a combined track.

Military service members have unique requirements and obligations to consider when pursuing graduate medical education, which includes cardiothoracic surgery training. Some branches of the US military do not allow students to enter integrated programs, preferring surgeons to have foundational training in general surgery. Therefore, most military surgical trainees go through the traditional pathway. However, there are some partnerships between certain cardiothoracic training programs and the military that are designed to be mutually beneficial. For example, the US Air Force has partnered with the University of California, Davis, so Air Force members can enter that I-6 program.²³ A similar partnership exists between the US Army and the traditional cardiothoracic surgery fellowship program at the Brigham and Women's Hospital.²⁴ Like with nonmilitary trainees, mentorship, ideally from senior military surgeons, is important for this group.

Conclusions

There are multiple pathways to become a cardiothoracic surgeon in 2025, and all can lead to a successful and rewarding career. The best pathway for a given trainee should be individualized based on interests, level of certainty about choice of specialty, and other priorities for training and education. Each trainee should take time for introspection, especially considering one's own learning style. Often, having an open and honest conversation with a trusted mentor in the field of cardiothoracic surgery can be the most important step for a student.

Conflict of Interest Statement

The authors reported no conflicts of interest.

The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.