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The mission of the center: 1. Offering state-of-the-art medical services to the Egyptian people, particularly the underprivileged and vulnerable age-groups. All services are free of charge. 2. Training a generation of young Egyptian doctors, nurses, and scientists at the highest international standards. 3. Advancing basic science and applied research as an integral component of the program and promoting biomedical research in Egypt. The second phase of the Aswan Heart Centre (AHC) from Magdi Yacoub Foundation (MYF), together with the Chain of Hope and the European Heart for Children Global Forum, has officially opened. The modern stateof the-art Heart Center offers adults with CV diseases and children with CHD treatment, all free of charge. The AHC is a compact, four-floor building that meets the highest international standards and offers all the subspecialties in cardiology such as cardiovascular imaging suite interacting echo, fully upgraded cardiac cath labs, and cardiac surgery rooms. Furthermore there is a pediatric intensive care unit and new outpatient clinic that preserves the dignity of the patients and their family members, while at the same time offering them the necessary comfort. 11,000 patients have been examined in the outpatient clinic. 1,326 cardiac catheterizations and 783 open heart procedures have been performed, of which 40% were pediatric procedures. Here we describe a case of a myocardial bridge in a young adult with hypertrophic cardiomyopathy: using coronary pressure measurements to guide decision-making. Patient History A 24-year-old female presented with a two year history of progressive shortness of breath and exertional angina, especially after meals. Diagnosis Physical examination was unremarkable apart from an apical fourth heart sound and a systolic murmur over the left sternal border that did not radiate to the neck vessels. A 12-lead electrocardiogram showed left ventricular hypertrophy and strain. Echocardiography showed assymetric left ventricular hypertrophy with a maximal thickness of 22 mm at the basal interventricular septum, systolic anterior motion (SAM) of the anterior mitral valve leaflet and a resting peak systolic gradient across the left ventricular outflow tract (LVOT) of 92 mmHg consistent with the diagnosis of hyper- trophic obstructive cardiomyopathy (HOCM). The patient had no family history of hypertrophic cardiomyopathy (HCM) or sudden cardiac death (SCD). Genetic testing revealed a myosin-binding protein C Glu441Lys missense mutation. A two-month trial of bisoprolol – titrated up to 7.5 mg/day – failed to improve her symptoms. Accordingly, surgical septal reduction therapy (extended septal myectomy) was advised. Treatment Preoperative coronary angiography – which is routinely performed as part of pre-myectomy work-up at our institution – revealed a myocardial bridge affecting the mid-segment of the left anterior descending (LAD) artery with near-complete obliteration of its lumen during systole that apparently did not continue into diastole. Three septal perforators arising from the mid-segment of the LAD artery showed similar complete “squeezing” during systole (Fig. 1). Thermodilution-derived coronary flow reserve (CFR) – measured invasively using a pressure/temperature sensor-tipped 0.014-inch wire (Radi PressureWire™ – St. Jude Medical, Inc.; St. Paul, Minnesota) and dedicated software (Thermo™ package) Charity Cardiology was significantly impaired in the LAD territory (1.23). The index of microcirculatory resistance (IMR) – measured using the same wire and software package – was also abnormal (53), denoting significantly elevated microvascular resistance which – on its own – can explain the blunted CFR values. Conventional fractional flow reserve (FFR) in the LAD was 0.91, however, diastolic FFR (derived from diastolic rather than mean aortic and distal LAD pressures) was 0.75 (Fig. 3). A decision to perform surgical unroofing and full mobilization of the tunneled segment of the LAD artery during extended septal myectomy was made based upon the above findings. Repeat coronary angiography four weeks after surgery revealed complete relief of the mobilized segment of the LAD artery – with no obliteration during systole (Fig. 2). Repeat CFR, IMR and diastolic FFR measurements showed significant improvement – measuring 1.7, 21 and 0.98 respectively (Fig. 3). Six months after surgery, the patient reports significantly improved exercise capacity with complete freedom from angina symptoms. Discussion Myocardial tunnels are frequently encountered in patients with hypertrophic cardiomyopathy with a reported prevalence of up to 40% in some post-mortem series 1–3. The incidental finding of a myocardial bridge on coronary angiography does not seem to carry an adverse prognosis or increased risk of SCD in this patient population 3, 4, and accordingly should not on its own warrant intervention 5. However, in patients with HCM and myocardial bridging presenting with angina as a prominent complaint, the physiological significance (i.e. ischemic burden) of such a finding should be carefully evaluated. Accurate identification of the small subset of patients with ischemia-producing myocardial bridges followed by surgical management improves symptoms considerably 6, 7 and may arguably reduce the risk of SCD 8, 9. Establishing a causal link between the presence of AXIOM Innovations | December 2013 | www.siemens.com/angiography  53


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