Question 11#

A 24-year-old IV drug user presents to hospital with a 6-week history of fever, rigors, and general malaise. On admission his temperature is 38°C. His venous pressure is elevated to the angle of the jaw with prominent V waves. You hear a loud systolic murmur at the lower left sternal edge, which is louder on inspiration. There is mild pedal oedema. Blood cultures grow Staphylococcus aureus in all six bottles. An initial transthoracic echocardiogram followed by a transoesophageal echocardiogram show no obvious vegetation and severe tricuspid regurgitation (TR). Nonetheless, he has 6 weeks of intravenous antibiotics with resolution of his sepsis. There are no embolic complications. He is now asymptomatic.

The following are all appropriate considerations for tricuspid valve surgery except:

A. Persistent symptoms with reasonable right ventricular dysfunction

This patient has severe isolated primary tricuspid regurgitation. Indications for surgery are shown in below box. Evaluation of RV dimensions and function must be conducted. Patients with RV dysfunction can be identified by various indices including a TAPSE (<15 mm), tricuspid annular systolic velocity <11 cm/s, and RV end-systolic area >20 cm2 .

ESC Guidelines 2012

Question 12#

Which one of the following transthoracic echocardiographic parameters does not suggest severe aortic regurgitation?

A. Vena contracta 0.50 cm

The following parameters suggest severe aortic regurgitation:

• Central jet width >65% of LVOT
• Vena contracta >0.6 cm
• Pressure half time <200 ms
• Holodiastolic aortic flow reversal in descending aorta
• Moderate or greater LV enlargement (BSE guidelines for chamber quantification give 6.4 cm as the lower limit of moderate LV diastolic enlargement in men)
• Regurgitant volume ≥ 60 mL/beat
• Regurgitant fraction ≥50%
• Effective regurgitant orifice area ≥0.3 cm²

Question 13#

During your CCU ward round you review a 72-year-old man with known aortic stenosis who presented with angina. He has been referred for aortic valve replacement. He has heard that there are different types of valve replacement and asks which is best.

Which one of the following statements is false?

A. A mechanical prosthesis is preferred for patients with hyperparathyroidism

A mechanical valve is preferred in patients for whom redo valve surgery would be high risk (LV dysfunction, previous CABG, multiple valve prosthesis). Any valve replacement carries risk, and in deciding whether a mechanical or biological valve is best a number of factors should be considered. The choice is mainly determined by estimating the risk of anticoagulant-related bleeding and thromboembolism with a mechanical valve compared with the risk of structural valve deterioration with a bioprosthesis. The ESC Guidelines 2012 are as follows.

In favour of mechanical prosthesis:

• Desire of the informed patient and absence of contraindication for long-term anticoagulation
• Patients at risk of accelerated structural valve deterioration, including young age (<40 years) and hyperparathyroidism
• Patients already on anticoagulation because of other mechanical prostheses
• Patients already on anticoagulation because at high risk for thromboembolism
• Age <60 years (aortic prosthesis) and <65 years (mitral prosthesis). In patients aged 60–65 years who receive an aortic prosthesis and those between 65 and 70 years in the case of mitral prosthesis, both valves are acceptable and the choice requires careful analysis of factors other than age
• Patients with a reasonable life expectancy (>10 years), for whom future redo valve surgery would be high risk.

In favour of bioprosthesis:

• Desire of the informed patient
• Unavailability of good-quality anticoagulation (contraindication or high risk, unwillingness, compliance problems, lifestyle, occupation)
• Reoperation for mechanical valve thrombosis despite good long-term anticoagulant control
• Patients for whom future redo valve surgery would be low risk
• Limited life expectancy (lower than the presumed durability of the bioprosthesis), or age >65 years (aortic prosthesis) or >70 years (mitral prosthesis)
• Young women contemplating pregnancy

Question 14#

A 23-year-old man with transposition of the great arteries underwent a Mustard operation during childhood. Three months previously he had a stent for a baffle stenosis. He attends outpatient clinic. He is undergoing a root canal procedure the following week and his dental surgeon has asked whether he needs prophylaxis for infective endocarditis (IE) before the procedure. He has a history of penicillin allergy.

What would you recommend?

A. No antibiotic prophylaxis required

According to ESC guidelines, antibiotic prophylaxis is considered for those at highest risk for infective endocarditis (e.g. prosthetic valve, previous endocarditis, cyanotic congenital heart disease, or congenital heart disease with complete repair and with prosthetic material insertion within the last 6 months or if there is a residual defect after a repair with prosthetic material), those are undergoing high-risk procedures (dental procedures involving perforation of oral mucosa or manipulation of the gingiva or the periapical region of the teeth). Antibiotic prophylaxis is no longer recommended for other procedures. Cephalosporins should not be used in patients who have had anaphylaxis, angio-oedema, or urticaria due to use of penicillin and ampicillin.

Question 15#

A 38-year-old IV drug abuser presents with a 1-week history of malaise, fatigue, and rigors. His temperature on admission was 38.5°C. Examination revealed a pan-systolic murmur which was loudest at the left sternal edge. Three sets of blood cultures were taken. Transthoracic echocardiography (TTE) showed vegetation on the tricuspid valve with moderate TR.

Which one of the following organisms is most likely to be positive in blood cultures?

A. Streptococcus sanguis

Approximately 85% of IE cases are culture-positive. Staphylococcus aureus is the most common cause in IV drug abusers. The HACEK group is the most common cause of culture-negative endocarditis. Candida endocarditis is a severe manifestation of systemic candidiasis and is the most common cause of fungal IE.