Sylvana De Mik

SDM-tools (OVIDIUS) trial. In addition to the DSTs, participating vascular surgeons and physician assistants are offered a practical training in SDM with a patient actor under the guidance of a medical psychologist. Chapter 4 details the stepped-wedge cluster randomised design of the OVIDIUS trial. This design implies that not patients but medical centres are randomised every two to four months to start using the DSTs. This ensures that at the end of the study all medical centres have implemented at least some of the DSTs and thereby a certain level of SDM. The level of SDM is measured from audio-recordings of surgeon-patient encounters prior to and after implementation of the DSTs. Currently, we are in the second half of patient inclusions.

Part II: Improving risk communication with vascular surgical patients
In pursuance of advancing SDM in vascular surgery, we also focussed on the harmonization and improvement of risk communication. Understanding the risks involved is a prerequisite for patients to be able to weigh the benefits of available treatment options against the potential harms. Vascular surgeons are legally bound to discuss the most frequent and most severe complications with their patients prior to treatment. Therefore, in chapter 5, we studied which complications following treatment for AAA, CAD, IC and VV vascular surgeons judged as major complications. The participating vascular surgeons were able to reach consensus on 9 to 12 major complications per vascular surgical disease. These major complications mostly appeared to depend on the severity of the disease evaluated, or were treatment-specific. Hence, we recommend all specialties to develop specific sets of major complications for the diseases they treat and to discuss these with their patients. However, it is imperative that the opinion of patients is taken into consideration when these sets of major complications are developed. In chapter 6, patients diagnosed with an AAA classified potential complications following treatment for AAA based on severity. When comparing the ten most severe complications classified by these patients with the 12 complications following treatment for AAA judged as major by the vascular surgeons, both groups agreed upon nine complications. These complications, presented in alphabetical order, are; aneurysm rupture, below ankle amputation, bowel lesion, heart failure, myocardial infarction, peripheral bypass surgery, renal failure, spinal cord ischemia, and stroke. Vascular surgeons should discuss these complications with their patients while deciding between surgical options and conservative therapy. Thus, the complications discussed with patients can be harmonized among vascular surgeons, while also allowing patients to weigh effectively the benefits of treatment against the harms they themselves deem important.

Vascular surgeons should discuss these risks with patients in a clear and understandable manner. Patients best understand risks when they are presented using clear definitions, absolute numbers and normal frequencies (for example 2 out of a 100 patients). Unfortunately, the reporting quality of complications and mortality following treatment for AAA, as presented in chapter 7, varied substantially between publications. This makes it difficult for vascular surgeons to extract from medical literature the information necessary to communicate risks in an understandable manner with their patients. Recommendations are made to assist future authors on improving the reporting quality in favour of risk communication. For example, we recommend adherence to existing reporting guidelines such as the CONSORT statement and SVS reporting standards. In addition, it is important authors clearly state whether they are reporting the number of patients with complications or the number of events, as patients may develop more than one complication.

Part III: Benefits and harms of yearly imaging surveillance following endovascular aortic aneurysm repair
For patients that are weighing the benefits and harms of undergoing treatment for AAA, it is important to know that one of the downsides of undergoing endovascular aortic aneurysm repair (EVAR) entails the need for yearly imaging surveillance. Since 22% of patients following EVAR develop complications that require reintervention, both international guidelines and the instruction for use manuals from stent graft manufacturers recommend yearly imaging surveillance. In chapter 8, our systematic review of the available literature, uncovered that patients following EVAR who are compliant to yearly imaging surveillance have a statistically significant higher reintervention rate compared to patients who are non-compliant, with a risk difference of 4% (95% CI [1-7%]). However, this higher reintervention rate does not appear to protect against mortality, since patients compliant to yearly imaging surveillance have a statistically significantly higher mortality rate compared to patients who are non-compliant, with a risk difference of 3% (95% CI [1-5%]). Thus, yearly imaging surveillance for all patients following EVAR seems to lead to additional reinterventions, which can cause complications by itself. In many cases, reintervention would have taken place irrespective of compliance to surveillance, since imaging was performed in between scheduled surveillance moments because the patient had presented with symptoms. Therefore, it stands to wonder, if yearly imaging surveillance is necessary for all patients following EVAR. Perhaps imaging surveillance frequency can safely be reduced for a select group of patients.

In chapter 9, we present the outcomes of our survey evaluating the available EVAR follow-up protocols used in 17 medical centres in the Netherlands. This survey shows that according to hospital protocols all patients undergo follow-up imaging within the first three months following EVAR. In 16 out of 17 medical centres, patients were to return for imaging surveillance each year. One medical centre had patients return every five years if first postoperative imaging did not show any abnormalities. Despite the adherence of all except one medical centre to yearly imaging surveillance following EVAR, all vascular surgeons agreed that imaging surveillance frequency may be reduced for some patients. However, they did indicate that more evidence is required to select these patients. This chapter also presents the study protocol of the ‘Observing a Decade of Yearly Standardized Surveillance in EVAR-patients with Ultrasound or ct-Scan’ (ODYSSEUS) study. In this study, researchers will collect reintervention, mortality and imaging surveillance data from the medical records of patients with an asymptomatic infrarenal AAA who underwent EVAR between January 2007 and January 2012. As these patients have already had five to ten years of follow-up, we will be able to study whether imaging surveillance may safely be reduced in patients with a normal first postoperative computed tomography angiography. The result of the ODYSSEUS studies are expected to become available in 2021.

Future perspectives

This thesis aimed to advance the use of shared decision-making (SDM) and risk communication in vascular surgery. The first steps towards this advancement have been made through the research presented in this thesis, which include: the development of different decision support tools for four vascular disorders, harmonization of the major complications that need to be discussed with patients while deciding on AAA surgery, recommendations to improve the reporting quality of complications and mortality in literature. However, additional steps are necessary to further improve SDM and risk communication between vascular surgeons and patients.

First, SDM is often misinterpreted by surgeons and patients, as SDM is often mistaken for informed decision-making or the informed consent procedure. Therefore, it is important that the actual meaning and value of SDM is promoted wherever possible. Fortunately, national campaigns, such as “Betere zorg begint met een goed gesprek”, (www.begineengoedgesprek.nl) have been launched by the Dutch Federation of Medical Specialists and the Dutch Patient Federation for this purpose. Also, SDM has been introduced as a structural part of the medical students’ curriculum. However, when these students become clinicians, they mostly adopt the manner in which current surgeons approach their patients. Hence, these surgeons must also be supported in practicing SDM.

Decision support tools (DSTs), such as decision aids, are helpful in providing information about the potential treatment options and in encouraging patients to consider about their preferences. 4,5 Whereas, consultation cards and decision cards provide an overview of the differences between treatment options and may function as a kick-starter for SDM to take place in the consultation room. 6,7 Nonetheless, merely providing surgeons and patients with DSTs will probably not improve the level of SDM, unless they also improve conversational skills necessary to actually practice SDM. 8 In preparation of the OVIDIUS trial, I too took part in the practical SDM-training as provided by our medical centre and can assure you that practicing SDM is not easy. However, the training helped by providing useful tips in evoking patients’ preferences and makes you aware of the pitfalls surrounding SDM. Not all medical centres participating in the OVIDIUS trial undergo SDM training prior to using the DSTs. Thus, it will be possible to compare the effect of the DSTs with and without SDM training. The OVIDIUS trial will probably show, as one of its main outcomes, that the combination of SDM training and DSTs use has the most beneficial effect on improving SDM. 8 Therefore, all clinicians should have access to and participate in SDM training. Preferably, this training should be offered as accredited courses available to all members of the medical profession.

Second, helping patients weigh the benefits and harms of potential treatment options is another important aspect of SDM. 9 Preferably, the benefits and harms vascular surgeons discuss with their patients are those that patients themselves deem important. Unfortunately, the benefits and harms patients find important are not always known. Even if they are known, they have received little attention in clinical trials. For instance, patients may find it more important to know if they are able to return home following aneurysm surgery, rather than whether they are still alive after fifteen years. Thus, we advise researchers of future studies to involve patients when designing new studies. This will assure that patient-relevant outcomes are studied, as well as those important to surgeons and researchers. 10 The results presented in these studies should be reported in such a manner that it allows surgeons to easily extract information and discuss this with their patients. Accordingly, future authors should pay close attention to their reporting quality. This can be achieved, for instance, by adhering to reporting guidelines and by taking note of our recommendations made in chapter 7.

Third, for vascular surgeons to discuss the available treatment options with their patients and help them weigh the benefits and harms, it does not only require an additional skill. 11 It also requires additional time. Notably, even though more treatment options have become available these last decades, the time to discuss these options during outpatient clinic visits has remained 10 minutes. In addition, hospital performance quality, among other items, is scored based on providing one-stop-shops. This means that on a single day, patients undergo additional examinations, are discussed in multidisciplinary meetings and receive their diagnosis and treatment plan. This benefits the patient as he or she leaves the hospital at the end of the day knowing the diagnosis and the plan to treat their disease. However, during this day there is no time for patients to contemplate the impact of this disease, discuss this with their relatives, and to consider their concerns and preferences regarding the proposed treatment.

Advancing the practice of SDM, therefore, requires changes in the manner in which the outpatient clinic is organised. 12 During the first visit, we recommend vascular surgeons to explain the possible treatment options to patients, including the benefits and harms. During a second visit, the patients’ preferences can be discussed and a treatment decision may be reached. In between these two visits, the patient should be offered the decision aid to consider his or her preferences. The additional time it takes to make this treatment decision, is likely to be regained during follow-up, as patients become more aware of the best treatment for them and experience less decisional conflict. 4,13,14 This will probably reduce the need for additional consultations in the future.

Fourth, another future development is the reduced frequency of follow-up consultations following endovascular aortic aneurysm repair (EVAR). This reduction is already stated in the recently updated Clinical Practice Guidelines on the management of abdominal aorto-iliac artery aneurysms from the European Society for Vascular Surgery (ESVS). In addition, the National Institute for Health and Care Excellence (NICE) guideline on Abdominal aortic aneurysm: diagnosis and management, from the United Kingdom, proposes not to offer EVAR for unruptured aneurysms to patients if they are suitable for open surgery. 16 The NICE guideline makes this proposal due to the increased need for reinterventions following EVAR.

The ongoing ODYSSEUS study, discussed in chapter 9, will likely show that imaging frequency can safely be reduced for patients with a normal first postoperative computed tomography (CT) following EVAR treated according to the instructions for use. This will expectantly provide sufficient evidence to support the statements made in the ESVS guideline. In a side-study of the ODYSSEUS study, not detailed in chapter 9, patients following EVAR are asked whether they appreciate a reduction in imaging surveillance frequency or prefer to undergo yearly imaging surveillance.

As this thesis focusses on SDM and risk communication in vascular surgery, it is probably obvious what the advice and perspectives for the future concerning the statements made in the ESVS and NICE guidelines will bring about. 15,16 Whether or not to reduce imaging frequency or to undergo EVAR for unruptured abdominal aortic aneurysms should be a shared decision made between the vascular surgeon and their patient.