HISTORY, CURRENT ILLNESS AND PHYSICAL EXAMINATION
The patient is a 79-year-old male diabetic with chronic kidney disease and chronic obstructive pulmonary disease as medical history of interest. In 2009, he underwent surgery for severe degenerative aortic stenosis and underwent aortic valve replacement with a Mitroflow No23 biological prosthesis. Postoperative transthoracic echocardiography (TTE) showed a normofunctioning valve with a maximum gradient of 25 mmHg. During follow-up, the patient remained asymptomatic until June 2016, when he presented with congestive heart failure in NYHA functional class III. The physical examination at that time highlighted RsCsRs with systolic murmur III/VI aortic with diastolic murmur II/IV. Normal abdomen. Lower limbs without oedema.

COMPLEMENTARY TESTS
ECG: was in sinus rhythm at 60 bpm with left ventricular hypertrophy and normal QRS width. TTE: severe aortic insufficiency of intraprosthetic origin with a maximum aortic gradient of 32 mmHg. Left ventricular function was normal and other findings included mild mitral regurgitation. Coronary angiography: coronary arteries were normal. Angio-CT: to evaluate the valve complex and vascular accesses, this test was performed with the following measurements: annulus: diameter 17 x 17.6 mm (mean 17.3 mm), circumference: 63.9 mm, circumference derived from the diameter: 20.3 mm; area: 320.9 mm2; area derived from diameter 20.2 mm; sinuses of Valsalva: left diameter 28 and height 10.7 mm, right diameter 28.8 and height 16.5 mm, non-coronary 27.2 and height 16.5 mm; height to coronary ostiums: left 4.3 mm, right 9.5 mm; LV outflow tract: diameter 18.7 x 23.2 mm. Distance from ring projection to coronary trunk exit 4.4 mm. Vascular accesses (minimum diameters): common iliac artery diameter 8 x 9.8 mm, right femoral artery diameter 7.1 x 7.2 mm, left common iliac artery diameter 7.6 x 7.7 mm, left femoral artery diameter 6.4 x 7.3 mm. Estimated risk scores STS 8 %, Euroscore 2: 14.98 %, Log Euroscore 48.25 %.

EVOLUTION
With the diagnosis of late prosthetic dysfunction (Mitroflow N23) with severe intraprosthetic insufficiency, the case was discussed in a medical-surgical session and taking into account the high surgical risk, the fact that it would be a reintervention and the patient's preference, it was decided to implant the Evolut N23 TAVI through right femoral access by means of a valve-in-valve procedure. The procedure is performed by placing a guidewire in the left coronary trunk during valve implantation and coronary angiography is performed to verify complete patency of the LMCA prior to prosthesis release. Both the placement and release of the prosthesis were carried out without incident, with angiography verifying correct positioning and the absence of significant regurgitation. After the procedure, the patient remained in the Intensive Care Unit for 24 hours with good evolution and early extubation. He was transferred to the cardiology ward where a control TTE was performed, which showed a normofunctioning prosthesis with a maximum gradient of 33 mmHg, without insufficiency. As the patient was asymptomatic, discharge was decided on the 7th day.

DIAGNOSIS
Implantation of an Evolut type transcatheter aortic prosthesis by means of a valve in valve procedure for treatment of late prosthetic degeneration (Mitroflow N23).
