In total, 23 centers (96%) were integrated within the adult cardiology service, but 8 (33%) counted on the participation of pediatric cardiologists. Table 1 shows the main strengths and weaknesses of the centers and comparisons between them stratified by level. Almost all centers had similar numbers of specialized units; there were no significant differences between centers except in the case of genetics and heart transplant units. Level 1 centers had more clinical cardiologists and more ACHD nurse specialists on staff, but two-thirds of centers and 40% of level 1 centers had no dedicated nursing support. In addition, less than 30% of the centers and only 40% of level 1 centers had structured transition programs. Most centers performed echocardiography and advanced radiologic imaging procedures in ACHD, but only 57% of level 2 centers had ergospirometry units, 43% had electrophysiology units, and 57% had cardiac catheterization units.

The units had been active for a median period of 11 [8-17] years; the median was significantly higher in level 1 centers. There was a total of 19 373 patients under follow-up. Level 1 and level 2 centers had a median of 1500 patients and 275 patients under follow-up (P <.001), respectively. In 2013, there were 503 surgical interventions, 448 therapeutic cardiac catheterizations, and 180 arrhythmia ablations in ACHD (83%, 72%, and 79% in level 1 centers, respectively). These figures account for 99% and 91% of the surgical interventions and therapeutic cardiac catheterizations in adults with CHD reported by the Spanish Society of Cardiology and the Spanish Society for Thoracic and Cardiovascular Surgery in the same year, respectively.

All level 1 centers and 43% of level 2 centers conducted specific multidisciplinary clinical sessions. In total, 92% of the centers participated in the training of cardiology or pediatric cardiology residents and 79% had published articles or presented communications at conferences on ACHD. Two centers have members in the Working Group on Adult Congenital Heart Disease,14 2 have participated in consensus documents,15,16 and 1 has participated in the development of the European Society of Cardiology clinical practice guidelines for the management of ACHD.17

Of the 24 centers, 18 (75%) participated in the registration of specific ACHDs seen in an outpatient clinic for a 2-month period. Seven level 1 centers (70%) and 11 level 2 (79%) participated in the registry. In total, 2289 patients (50% male) were included. Median age was 35 [25-45] years. There were no differences in age or sex between the 2 types of center, but age at diagnosis was significantly lower in level 1 centers (table 2). Of the patients, 32% had simple lesions, 44% had moderately complex lesions, and 24% had highly complex lesions. There were significant differences in the distribution of the level of complexity: only 27% of the patients attended in level 1 centers had simple lesions, whereas 46% attended in level 2 centers had simple lesions. In total, 47% and 37% of the patients attended in level 1 and level 2 centers had moderately complex lesions, respectively, and 26% and 17% had highly complex lesions, respectively (figure 3). In general, the most frequent diagnostic groups were Tetralogy of Fallot (12%) and aortic coarctation (11%), but there were also significant differences between the 2 types of centers; the most frequent diagnoses in level 2 centers were bicuspid aortic valve disease, ostium secundum atrial septal defect, and ventricular septal defect (figure 3).

Figure 3.

Comparison of complexity and specific heart disease between level 1 and level 2 centers. BAV, bicuspid aortic valve disease; OS ASD, ostium secundum atrial septal defect; TGA, transposition of the great arteries; VSD, ventricular septal defect.

(0.13MB).

In total, 77% of the patients had undergone previous cardiovascular intervention. The percentage was significantly higher in level 1 centers (79% vs 72%). More patients had undergone percutaneous procedures alone in level 2 centers. Age at the time of intervention was significantly lower in patients in level 1 centers. In addition, 517 patients (23%) had undergone reintervention during adulthood at a mean age of 31±13 years: 25% of these patients underwent reintervention in level 1 centers and 15% in level 2 centers. There were no significant differences between the 2 types of center regarding surgical or percutaneous reintervention (P=.581).

Regardless of the level of the center, all of the patients underwent electrocardiography and echocardiography at clinical assessment, but chest X-ray was only performed in 56% of patients and Holter monitoring in 19% of patients. Cardiac stress tests were performed in 830 patients (36%), although more were performed in level 1 centers (40%) than in level 2 centers (25%). Interestingly, 365 of the patients in level 1 centers (22%) underwent ergospirometry vs 3.8% in level 2 centers. Finally, a significantly higher percentage of patients underwent advanced radiologic imaging procedures in level 1 centers (56%) than in level 2 centers (31%).

The first ACHD health care network was founded in Canada in October 1991.18 Currently, it includes 15 centers, 8 of which are level 1, serving a population of 37 million. In the UK, there are 11 level 1 centers and 5 level 2 centers serving a population of 66 million.19 ACHD health care in the United States is less structured, but some European countries, such as the Netherlands, Germany, and Switzerland, have followed examples of Canada and the UK by establishing ACHD health care networks of level 1 and 2 centers.

In Spain, the development of the ACHD health care network has followed a similar course. The greatest growth occurred in the second half of the 2000s followed by a steady increase, demonstrating the high level of interest in this subspecialty. Although the recommendations of the European Society of Cardiology10 do not require centers to have their own transplant program as an indispensable condition for being considered level 1, advanced heart failure remains the main clinical problem in ACHD.20 Thus, 10 centers with a complete health care structure and advanced heart failure and transplant programs were designated as level 1. Therefore, there are 2.2 centers for every 10 million inhabitants in Spain. This ratio complies with the recommendations of the 32nd Bethesda Conference of 2001, which estimated that there should be 1 referral center for every 5 to 10 million inhabitants.21 The Spanish National Health System has recognized 9 of these 10 centers as CSURs; thus, if some of the other centers were designated as CSURs a more balanced geographic distribution would be achieved.

There are also 14 level 2 centers, making a total of 24 specialized centers. This figure fulfills the international recommendations of 1 regional center for every 2 million inhabitants.22 However, the geographic distribution of these centers is not optimal. As shown in figure 1, some regions do not have at least 1 center with specialized ACHD clinics. However, it may be the case that this information is incomplete and that other communities have their own projects to serve this population.

Several studies have attempted to quantify the current number of ACHD patients; a systematic review described a prevalence of between 1.7 and 4.5 patients/1000 inhabitants (mean, 3‰).23 Extrapolating these data, there would be around 120 000 ACHD patients in Spain. Our study shows that there were less than 20 000 ACHD patients under follow-up in the 24 registered centers. This figure is less than one-sixth of the total estimated. This information may be relevant, because an association has been found between the referral of ACHD patients to specialized centers and significant reductions in mortality.24 However, our results are similar to those of other developed countries.8,25 Although calculations based on population studies may be overestimated, the abovementioned disparity suggests that many ACHD patients are not under active follow-up in experienced units.

Spanish centers have a health care structure comparable to that of other developed countries. At the national level, the mean number of surgical interventions, percutaneous therapeutic procedures, and arrhythmia ablations in level 1 centers were 38, 24, and 15, respectively. These means are similar to those of the Canadian health care network centers (31, 32 and 15)8 and 18 selected European centers.9 Moreover, surgical interventions and percutaneous procedures in adults with CHD that were performed in specialized clinics accounted for 99% and 91% of those reported by the Spanish Society for Thoracic and Cardiovascular surgery and the Spanish Society of Cardiology registries, respectively.11,12 However, 28% of percutaneous procedures, 21% of arrhythmia ablations, and 17% of surgeries were performed in level 2 centers. The clinical practice guidelines recommend that these therapeutic procedures should be performed in centers with more experience, and so a greater number complex procedures should be performed in level 1 centers.26

To meet the needs of ACHD patients, the number of centers and the number of patients being monitored should be taken into account, as well as the provision of the human and material resources required.18,27,28 This study shows that Spanish centers comply with international recommendations and pay special attention to specific training. The main weaknesses detected were the low percentages of ACHD nurse specialists on staff and structured transition programs. These aspects could be interrelated because nursing staff are the main human capital in structured transition programs. In Spain, the lack of development of specialized training programs in nursing is common to other specialties. Although the clinical assessment process was similar in level 1 and level 2 centers, the main differences were related to complete cardiopulmonary assessment or the use of advanced radiologic imaging procedures. Moreover, none of the level 2 centers had their own heart transplant and advanced heart failure programs, suggesting the need for all centers to be interconnected in a health care network.

The distribution of specific CHDs in adults continues to be a matter of speculation. Most estimates are based on population studies. It is generally assumed that more than 50% of ACHD patients have simple lesions, 30% to 40% have moderately complex lesions, and less than 15% have highly complex lesions.14 However, population studies have important methodological limitations. The International Classification of Diseases system does not always differentiate a nosological entity from a variant. Furthermore, it is not always easy to differentiate congenital lesions from acquired lesions, particularly in the setting of valvular abnormalities. Thus, the main source of uncertainty involves simple lesions.

In addition, the information provided by the records may have a selection bias. Most of the registries come from high-volume tertiary hospitals, where there may be an overrepresentation of more complex lesions. This study describes an unselected sample of consecutive patients with ACHD attended in 18 Spanish centers. It should be noted that 24% of the patients had highly complex lesions, 44% had moderately complex lesions, and 32% had simple lesions. The results show that there were more patients with more complex lesions in level 1 centers and more patients with simple lesions in level 2 centers. However, 17% of patients in level 2 centers had very complex lesions. The guidelines recommend that these patients should undergo comprehensive follow up in centers with the greatest experience. A common health care model, advocated in Europe, Canada, Australia, and the United States, recommends that all adults with CHD should be assessed by a multidisciplinary team in a specialized center, thus allowing the individual determination of the appropriate level of care and follow-up.2

The main limitation of this study is due to the survey methodology used, which, in some cases, may have relied on estimated data. However, the fact that therapeutic procedures accounted for 99% and 91% of those reported by national Cardiac Surgery and Cardiac Catheterization registries, respectively, suggests that these data are relatively reliable. In addition, although only 75% of the centers participated in the specific heart disease registry, the percentage was similar in level 1 and level 2 centers (70% and 79% respectively). This result provides a reasonably accurate snapshot of ACHD patients currently under follow-up in Spain, including centers with a widely heterogeneous volume of patients and activities. Although special care was taken to avoid duplication in the registry, some patients followed up in level 2 centers may have also been followed up in level 1 centers. The data obtained show clinical activity during a specific period and cannot be used to estimate the flow of patients within the health care network. In addition, the survey did not include palliative care and advance health care directives or specific rehabilitation programs.