The medical field is in a state of constant evolution—as it should be—as new diagnostic and treatment methods are developed to help clinicians manage conditions that would a decade ago have ended very badly for the patient. Formal education and training, however, rarely catch up to the latest technological advancements, leaving many to fill the knowledge gaps themselves.
The need for continuing medical education (CME) of doctors is well recognised, although its extent, quality and scope and input from professional organisations (mandatory/voluntary CME) varies greatly between countries [1, 2i]. This statement is true for nearly all medical specialities and particularly the diagnostic aspect, since diagnostic devices are becoming increasingly complex, necessitating special and extensive training that goes beyond correct interpretation of results. However, this does not hold true for all technical solutions as there is also a push towards simplifying diagnostic procedures, especially in general practice settings, where the resources and time dedicated to each patient are limited. Said tools can be likewise suitable for specialists, e.g. for initial screening that may not require in-depth analysis of diagnostic results.
A good example would be diagnosis of peripheral artery disease (PAD) or, commonly, lower-extremity artery disease (LEAD). There are several distinct diagnostic approaches, which greatly differ in their complexity and cost-efficiency. The most comprehensive is arterial angiography as it offers excellent detection (between 89 and 100%) and specificity (from 92 to 100%), but it can be prohibitively expensive in most cases and might be entirely inappropriate (possibility of contrast-induced nephropathy in those with renal dysfunction) for some patients [3, 4, 5]. A CT may be substituted for an MRI, eliminating both the dangers and complications associated with ionising radiation and contrast medium, if none is used, but unfortunately still retaining the high-cost.
Another, far cheaper method is physical examination – pulse palpation (femoral and posterior tibial artery). Such approach, while reasonably accurate if performed by a skilled examiner (inaccuracy and the rates of false positives and misdiagnosis were significantly higher in physicians without specialist training), is still unreliable and does not offer an acceptable level of accuracy . A far better one, in terms of accuracy and cost-efficiency, is measuring Ankle-Brachial (pressure) Index (ABPI or ABI).
This can generally be performed in two ways: using a Doppler probe and a sphygmomanometer, or with an oscillometric-plethysmographic diagnostic device. The first option is accurate and reliable, but only if performed by a competent examiner and can take up to 30 minutes, limiting the number of patients assessed and time dedicated to each one, while the accuracy of the latter is not predicated on the examiner’s skill and can be performed in 1 minute (greater usability of preventive screening) [7, 8]. Both methods can be performed at a cardiology office, but, again, the latter has a significant edge in time efficiency and convenience.
What should a cardiologist not forget when examining a patient?
Today, the need for a holistic approach to examinations is greater than at practically any time before, not just in the field of cardiology, which is nevertheless influenced by advancements in other fields. One such example would be diabetology and the growing wealth of knowledge of how diabetes affects cardiovascular health and contributes to the incidence, prevalence, morbidity and severity of outcomes of various cardiovascular diseases (CVDs), primarily PAD/LEAD.
Diabetes mellitus has serious deleterious effects on PAD/LEAD. It is estimated that at least 20% of diabetic patients have PAD, although that number is generally recognised as being too low since the study that published the aforementioned number only encompassed symptomatic cases of the disease . However, they only represent a minority of manifestations of PAD (only 10% of patients have typical symptoms) since the disease is more often entirely asymptomatic (about 40% of cases) or presents symptoms that could be attributed to other medical conditions (the remaining half of cases) [10, 11].
Cardiologists should be cognisant of these facts (including the contribution of other risk factors besides diabetes), specifically the prevalent asymptomatic nature when examining a patient referred to them (for any other cardiovascular conditions, not purposely for PAD). But are they? One study has indicated that PAD is often under-recognised in patients with acute coronary syndrome (ACS)—in spite of the well-recognised benefits of timely diagnosis of the disease in cardiac patients [12, 13]. The situation is even worse in other (non-cardiac) types of patients: many diabetics are undiagnosed and a considerable number of individuals with chronic lower-extremity wounds do not receive an ABI assessment and are consequently given improper treatment [14, 15, 16].
The first line of defence against untimely diagnosis of PAD should be general practitioners who are most intimately acquainted with the patient’s health history and inclusion in risk groups (decent indicators of increased probability of the disease in the absence of overt symptoms). The situation is quite different in reality, primarily due to a lack of resources or awareness of modern, time and cost-effective diagnostic methods for measuring ABI [10, 17]. The next line is comprised of cardiologists who should have significant interest in ascertaining the PAD-status of their patients, stemming from comorbidity of PAD with other CVDs.
Many patients (up to 42% of them) with coronary artery disease (CAD) also have PAD and suffer worse outcomes and have higher mortality rates than those with either of the two conditions [18, 19, 20, 21]. Next, patients with PAD and a history of stroke and transient ischaemic attacks (TIAs) fare worse in comparison with those with CAD and a comparable history of cerebrovascular conditions . There is more: a study that compared event rates of outpatients with atherothrombosis over a 1-year period found that about 21% of patients with a history of cerebrovascular disease and diagnosed (symptomatic) PAD had a cardiovascular event or required hospitalisation, while the same fate befell only 13% of those with comparable medical history, but without PAD .
The argument for under-recognised prevalence of PAD in patients with cardiovascular issues is further supported by findings of SCALA (Systemic Risk Score Evaluation in Ischaemic Stroke Patients) and PATHOS (Polyvascular ATHerothrombosis Observational Study) studies: 51% of patients in the former and 33.5% in the latter study had a low ABI score (possible PAD), but only about 10% had typical symptoms [24, 25]. Lastly and unsurprisingly, the ABI score is recognised as an important indicator of overall cardiovascular health and can improve cardiovascular risk prediction (beyond the Framingham Risk Score) .
Cardiologists are in a pivotal position to identify possible PAD on the basis of an ABI assessment in a timely manner and uniquely equipped for providing effective treatment and management, particularly in patients with other comorbid cardiovascular issues.