The progress of percutaneous intervention of coronary arteries in acute myocardial infarction (AMI) has led to a substantial reduction of mortality of these patients worldwide. It currently represents the best example of an important role of interventional cardiology in theimprovement of outcomes in management of acute coronary syndrome (ACS). Such a trend of reducing mortality from AMI has been observed in Croatia, as published in the latest report by the State Bureau of Statistics, where for the first time it was recorded that cardiovascular diseases (CVD) had a frequency of less than 50% in the mortality and morbidity in the entire population, while mortality from AMI was for the first time lower than the mortality from cerebrovascular diseases (1). Given that over the last few years there has not been a serious public campaign on primary prevention of CVD, and that smoking and obesity still remain a significant public health problem, such results are most likely a direct consequence of the development of the national network of primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction with (STEMI) established in cooperation of the Working Group (WG) for the acute coronary syndrome of the Croatian Cardiac Society (CCS), the WG for interventional cardiology of the CCS and the Ministry of Health of the Republic of Croatia in 2005 which topic was discussed in this journal recently (2). This is evidenced by the reports of cooperating institutions, where the mortality from AMI in the Croatian hospital centres from Northwest region before the introduction of the network was 15-20%, and now it accounts for 7-8%, and it primarily relates to elderly patients with several comorbidities who have not been previously referred for PCI (3). Currently, the national acute-PCI network covers more than 70% of the national territory with more than 2,500 STEMI patients treated across the country on an annual basis (4). The number of treated patients is increasing significantly every year and during the year 2013, we expect full coverage of the national territory after involving the intervention centers in Western Slavonia and the Dubrovnik-Neretva County. The increase in the number of treated patients to more than 3,000 per year, in cooperation with growing evidence on benefits of earliest PCI intervention in management of the non-ST-segment elevation acute coronary syndrome (NSTE-ACS) (5), will inevitably become an additional burden for overstretched financial budgets of institutions that carry out of the interventional activity in the network. One could reasonably expect the slowdown in overall network development, particularly in concern to introducing of novel technologies and devices for interventional cardiology in Croatia. Pointing out the problem of mis-evaluated professional engagement of invasive cardiologists, which is often represented as equal with other routine and non-invasive diagnostics, although this is a well established fact since the first PCI was performed in Zurich in 1977 by Andreas Gruentzig. This will inevitably lead to a shortage of invasive cardiology and particularly cooperative staff. Cumulative effects of dynamics will inevitably lead to a shortages in material, equipment and personel enrolled in invasive cardiology, particularly the assistant staff. The assistant staff along with the surgeons work in the stressful environment of catheterization and electrophysiology cardiology labs, exposed to X-ray (6), with being obligated to perform their daily routine participation in the ward work, medical care and diagnostics, which cumulatively leads to lessened interest for career in interventional cardiology in future generations.

Although the indications and benefit of primary PCI in acute coronary syndrome (ACS) is unquestionable and supported by a series of high-quality evidence, position of PCI in chro nic coronary heart disease (CHD) still remains the subject of great debate among various subspecialties (interventional cardiology, cardiac surgery and noninvasive cardiology). Following the publication of the results of the COURAGE trial in 2007, that included randomization of 2,287 patients from primer pool of 30,000 patients, there were no significant differences reported in major adverse events rates between the optimal conservative therapy vs. PCI, and one would expect that the number of PCIs in patients with chronic CHD will start to fall (7). However, reports from the countries of Western Europe and the United States of America with well organized systematic database monitoring of coronary interventions showed a trend of remained number of PCI in the management of chronic CHD over the last 5 years. Reported frequency of 45% of patients with chronic CHD who were treated with PCI following the publication of the COURAGE trial was almost identical to the situation prior to the publication. It is interesting to note that only 30% of patients with stable angina pectoris that underwent PCI had any of the coronary flow reserve tests prior to the intervention (8) in reports from North American registries. It is impossible to make comparisson or analyze similar set of data from Croatia due to the lack of a national registry. Nevertheless, the data from intervention centers which were presented at meetings of professional societies showed that the exercise tolerance test on treadmill is almost as a rule performed prior to coronarory angiography and PCI. Burning issue in concern to underscored the use of interventional diagnostics and potentially unnecessary interventions in developed countries luckily does not seem to be the challenging issue in Croatia, especially on the bases of limited resources for total budget covering the interventions. In particular, the share of patients with primer PCI interventions in Croatia continuously growths, whilst the number of interventions for chronic heart disease stagnates.

Interventional treatment in stable CHD is certainly one of the most controversial issue in the management of CHD nowdays. In addition to conservative medical therapy, coronary bypass surgery and stent implantation, the brand new concepts like the drug-coated balloon (“drug eluting” or “drug coated balloons” — DEB) for the treatment of in-stent restenosis, and de novo coronary lesions. For the time being, “only DEB” concept has been tested for the treatment of bare metal stent or drug eluting stent restenosis, and there is data about the superiority of DEB with an option for bare metal stent implantation over drug eluting stent implantation in small calibre coronary arteries with a diameter 2.8 mm or less (9). In addition to balloon dilation and the use of DEB, the so-called “spot-stenting” or “provisional” stenting reported in the literature offered the concept of intervention solely to culprits of major dissections and narrowing responsible for symptoms of coronary ischemia (10). One must not disregard the concept of bioabsorbable vascular stent (BVS), which represents a provisional made from absorbable material placed in the coronary artery. Following its absorption, coronary artery is expected to develop ameliorative remodeling, in order to decrease the potential for developing the restenosis or thrombosis to a minimum (11). In 2012 BVS was officially registred in the Croatian market, but due to relative high price, only a low number of them have been implanted. However, all of these techniques require prospective randomized studies. In consideration to chronic CHD, we share an opinion that the modality of revascularization treatment (PCI, cardiac surgery or medications only) should certainly be left to “heart team” (invasive and non-invasive cardiologists and cardiac surgeons). Team approach should ensure better adherence to guidelines and optimal treatment, which has been proved in some low-volume centers without invasive cardiac surgery (12), especially in high-risk groups of patients with diabetes.

Doubts regarding drug eluting stents (DES) implantation and increased risk of stent thrombosis raised by the results published by some major global registries in 2006 and 2007 were completely eliminated in favour of DES by the development of the third generation of DES and results published by registries and randomized studies which included patients with chronic CHD and patients with ACS (13). On the contrary, in the new guidelines of the European Society of Cardiology (ESC) for the treatment of STEMI, DES was for the first time assigned the level IIa recommendation (“should be used”) with the highest level of evidence A, as well if there were no clear contraindications to the long-term use of dual antiplatelet therapy (14). The 2010 Guidelines evidently prefer DES for interventional revascularisation in diabetic patients with recommendation grade I (“definitely to be used”) and level of evidence A (15). The frequency of DES among the implanted stents in Western countries today range between 65% (Germany) and 90% (Switzerland), and a relatively high frequency of 35% to 40% in countries with socio-economic circumstances similar to Croatia. Given the lack of a national registry, it is hard to estimate the exact share of DES in Croatia. Indirect appraisal gained through reports from major Croatian centers presented at professional symposiums and conferences (especially for the high-volume centers with a large portion of patients treated within the pPCI network) is estimated to be below the 10%. Reported significant reduction in rates of re-revascularization and long-term profile of major adverse events for groups of patients with complex lesions is in favour of DES use (diabetes, bifurcation lesions, long lesions in the narrow coronary arteries, the left main or aorto- ostial lesions which is estimated to be represented in more than one third of patients undergoing PCI). The necessary changes in the reimbursement of elective and acute interventional program in Croatia would allow an increase in the number of patients treated with DES, on the basis of substantial long term benefits offered.

The effectiveness of coronary interventions and implantation of various materials in the acute or chronic CHD is in part connected with the use of antiplatelet and anticoagulant therapy. During the past year a lot of new recommendations and changes were issued in antiplatelet therapy in interventional cardiology that have not been applied in Croatia so far, where clopidogrel, with proven resistance problem is for the time being the only available oral antiplatelet drug. Its wide administration is usually accompanied with aspirin, whilst ticlopidine is rarely used due to and unfavorable sideeffect profile. The most important recent improvement of antiplatelet therapy include the use of ticagrelor in ACS, regardless of invasive or noninvasive treatment strategy, as published in the PLATO trial and the latest ESC guidelines for the treatment of STEMI (14). Ticagrelor is not yet available in Croatia, and when it becomes officially available, the initial experience will be limited due to its relative high price. Prasugrel, an antiplatelet drug that became widely used in the Central Europe following the results of the TRITON study which showed its advanced efficacy over clopidogrel for the invasive treatment of ACS, however burdened by increased prevalence of bleedings (16). The later is also not available in Croatia.

Increasing number of drugs from anticoagulants, that mediates different steps of coagulation cascade group is being tested in prospective randomized studies and used for treatment of ACS. Currently, the efficacy and safety of otamixa ban, apixaban and rivaroxaban (17-19) in invasive treatment of ACS is being tested, while unfractionated heparin, bivaluridin, enoxaparin and fondaparinux are still the most common and most investigated medications and the only medications recommended in the guidelines (14). Bivaluridin is still not available in Croatia, so the majority of interventional procedures are performed with concomitant use of unfractionated heparin for interventions in acute STEMI, as well as for and stable chronic CHD. The use of enoxaparin or fondaparinux as an add-on to of unfractionated heparin is reserved in Croatia for interventions in NSTE-ACS, apart from very infrequent use of unfractionated heparin, as a single therapeutic approach. Anticoagulant medication with favorable ratio of efficiency (less clots) to safety profile (less bleeding) is still not available for interventional treatment, although most of the studies reported that treatment success rate of high-risk patients depends mainly on the time of referral to invasive treatment.

Evidence exists that the conventional two-dimensional coronary angiography is at some instances limited for recognizing the true risk of CHD, especially in concern to lesions of the left main coronary artery, bifurcational lesions and diffusely outspread multi-vessel disease. The introduction of novel diagnostic tools as intravascular ultrasound (IVUS) or fractional flow reserve (FFR) through specially equipped guidewire that detects the ratio of intracoronary pressure flow from upstream and distal to atherosclerotic stenosis has greatly helped the interventional cardiologists to make right decisions on treatment of subgroups of patients with CHD. Later technology offered reproducible objectivity for decisions of interventional strategies of those patients with multivessel disease and other complex lesions. The recently published FAME-2 study, the continuation of the well-known FAME study reported on superiority of FFR-guided intervention in patients with multi-vessel disease compared to conventional angiography. The use of FFR-guided PCI offered a significant reduction in a number of repeated revascularizations (20). One must underline the fact that the patients in the FAME-2 study were randomized in the course after the FFR assesment, apart from the FAME study which randomization was done prior to invasive procedure. Consequently, some of patients from FAME-2, that had multi-vessel disease with at least one clinically significat culprit lesion according to conventional PCI and/or FFR had the great deal of chance to be stratified to arm of conservative pharmacological treatments, due to loss of double-blinding by the operators and the patients. Despite the differences, both the FAME and FAME-2 proved the clinical value of functional evaluation of CHD significance, laying the ground for recommendation on need to foster the use of this technology in patients with multi-vessel stable CHD. Most of the centers from Croatia are sufficiently technically equippws for the use of FFR, however availability is scarce due to a high cost of such devices.

Interventional cardiology demonstrated indeed crucial advancements over the last few years, after reaching the topmost development in treatment of acute and chronic coronary artery disease it began successfully to be applied in many other fields of cardiovascular medicine by developing the technologies such as TAVI, MitraClip or cardioembolic protection. However, the constant debate about the treatment of chronic CHD by applying different strategies, accompanied by the development of new technologic and molecular concepts (DEB, BVS, stem cells, modulation of a inflammatory response), and continuous efforts in further improvement of efficacy and safety of ACS treatment, makes the CHD still an interesting issue for the society of interventional cardiologists. Similar trend is seen in Croatia as well; however, the limited budgets for interventional cardiology still causes unacceptably low percentage of DES’s usage, while the introduction of new emerging technologies and devices could not be established at the time being. Significant issue is related also with a limited use of the new generations of antiplatelets and anticoagulants recommended by the guidelines. The TAVI program has been successfully initiated, but in order to sustain or keep the quality of treatment, a number of implantations should be increased sufficiently. Assistance of overall cardiology community is necessary in order to maintain the present enviable results in managing ACS and also for the prosperous development of interventional cardiology mainly in accordance with the guidelines, but also in regard to using new technologies of treatment of coronary and structural heart disease that we must adopt.