|INTERESTING CASE REPORT
|Year : 2021 | Volume
| Issue : 3 | Page : 239-242
Paradoxical Infective Endocarditis of the Right Coronary Aortic Cusp in a Restrictive Ventricular Septal Defect: Bernoulli's Phenomenon Revisited
Debasish Das, Debasis Acharya, Tutan Das, Subhas Pramanik
Department of Cardiology, AIIMS, Bhubaneswar, Odisha, India
|Date of Submission||11-May-2021|
|Date of Acceptance||12-Jun-2021|
|Date of Web Publication||19-Oct-2021|
Department of Cardiology, AIIMS, Bhubaneswar - 751 019, Odisha
Source of Support: None, Conflict of Interest: None
We present the case of a 35-year-old female with small restrictive ventricular septal defect (VSD) presenting with prolonged fever for the last 1 month with vegetation on the right coronary cusp (RCC) of the aortic valve with flail aortic leaflet causing severe aortic regurgitation (AR). Her echocardiography done 1 year back had revealed the presence of small restrictive VSD with a gradient of 80 mm Hg without any prolapse of RCC or presence of AR. She did not have any early diastolic murmur of AR during 3 monthly routine follow-up in the cardiology outpatient department suggestive of previous aortic valve prolapse with AR in the aforesaid period before the infective endocarditis episode. Common sites of the vegetation in small restrictive VSD are right ventricular side of the interventricular septum, undersurface of the tricuspid valve, free wall of the right ventricle, and rarely the pulmonary valve on the low-pressure site of the shunt where the turbulent jet containing the bacteria slows down, and bacteria adhere the underlying endocardium. Normally, vegetation across any turbulent jet does not occur on the high-pressure site due to the reason that bacteria can not adhere to the wall across the turbulent jet in high-pressure zone, which sweeps away all the bacteria from the high-pressure zone to low-pressure zone. Paradoxical finding in our case was that vegetation was noted on the RCC of the aortic valve which was a high-pressure zone, which may be explained by only Bernoulli's phenomenon. Our case illustrates paradoxical vegetation on the RCC of the aortic leaflet in a patient with small restrictive VSD and is also a unique demonstration of left-sided endocarditis in a patient with left-to-right shunt.
Keywords: Infective endocarditis, right coronary cusp, ventricular septal defect
|How to cite this article:|
Das D, Acharya D, Das T, Pramanik S. Paradoxical Infective Endocarditis of the Right Coronary Aortic Cusp in a Restrictive Ventricular Septal Defect: Bernoulli's Phenomenon Revisited. J Indian Acad Echocardiogr Cardiovasc Imaging 2021;5:239-42
|How to cite this URL:|
Das D, Acharya D, Das T, Pramanik S. Paradoxical Infective Endocarditis of the Right Coronary Aortic Cusp in a Restrictive Ventricular Septal Defect: Bernoulli's Phenomenon Revisited. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2021 [cited 2022 Oct 5];5:239-42. Available from: https://jiaecho.org/text.asp?2021/5/3/239/328669
| Introduction|| |
Development of endocarditis requires the presence of three phenomena: presence of a turbulent jet from high-pressure zone to the low-pressure zone, presence of continuous bacteremia, and presence of immunocompetence in the host so that nidus is formed in a slow growing process. The bacteria can not adhere to the endocardium on the high-pressure site due to the presence of more turbulence which sweeps away the bacteria; after crossing the turbulent jet, bacteria adhere on the low-pressure zone. That is why vegetation in mitral regurgitation occurs over the atrial site of the mitral valve and ventricular side of an aortic valve in aortic regurgitation (AR). The same principle applies to the restrictive ventricular septal defect (VSD) where vegetation occurs over the right ventricular side of the interventricular septum (IVS), undersurface of tricuspid or pulmonary valve, right ventricular free wall but paradoxic finding in our case was large vegetation was noted on the right coronary cusp (RCC) of the aortic valve. The patient also did not have congenital bicuspid aortic valve or prior AR, which may be a predisposing factor for endocarditis in some cases. Bernoulli's phenomenon operating across the small restrictive VSD may be a plausible explanation behind the development of infective endocarditis over RCC- turbulent jet across the restrictive VSD generates a low-pressure zone around the overlying RCC and bacteria in the forward blood flow jet during ventricular systole across the aortic valve fall over the right aortic cusp due to this negative pressure, form a nidus and develop infective endocarditis. Local hemodynamics always plays a vital role behind pathogenesis as in our case we noted paradoxical vegetation of RCC in a case of small VSD.
| Case Report|| |
A 35-year-old female presented with prolonged fever for the last 1 month with the presence of long diastolic murmur over the precordium and was referred from a peripheral center. At the time of presentation, she had blood pressure of 150/60/0 mm Hg in the right arm supine position due to aortic runoff in acute AR with a pulse rate of 84 beats/min with the presence of holodiastolic murmur over the aortic area. Electrocardiogram was suggestive of left ventricular volume overload with prominent Q wave in lateral leads with concave ST elevation. Echocardiography revealed the presence of a small restrictive perimembranous VSD of 3 mm in size with left-to-right shunt with a gradient of 83 mm Hg [Figure 1] and [Figure 2] with a large (16 mm × 6 mm in size) friable vegetation attached to the RCC, freely mobile without calcification with flail RCC causing severe AR [Figure 3], [Figure 4], [Figure 5]. Laboratory examination revealed that she was mildly anemic with hemoglobin 8.9 g/dL, microcytic hypochromic in nature, total leukocyte count 13400/mm3 with neutrophilic leukocytosis, and normal platelet count with high erythrocyte sedimentation rate of 80 mm/h with elevated serum c-reactive protein. Urine routine microscopic examination was within normal limit without the presence of any casts. Blood culture grew the most common organism- Streptococcus viridians. The patient was treated with injection ceftriaxone 2 g intravenous daily for 14 days with injection gentamycin 80 mg intravenous twice daily for 7 days followed by oral fluoroquinolone for 4 weeks. The patient was advised to undergo aortic valve replacement with pericardial patch closure of VSD after 1½ months. During follow-up, the patient was afebrile; vegetation regressed with the development of calcification inside without much regression in the extent of AR. Our case thus illustrates paradoxical left-sided endocarditis in a left-to-right shunt due to small restrictive VSD.
|Figure 2: Gradient across the small ventricular septal defect of 82 mm Hg|
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| Discussion|| |
Patients with small restrictive VSD are advised by few pediatric cardiologists to undergo pericardial patch closure because they may acquire infective endocarditis in due course of time. Our case is an illustration of the same; a 35-year-old female with small restrictive VSD developed infective endocarditis of the RCC with severe AR secondary to flail RCC. Her echocardiography done 1 year back had revealed the presence of small restrictive VSD with a gradient of 80 mm Hg without any prolapse of RCC or presence of AR. She did not have any early diastolic murmur of AR during 3 monthly routine follow-up in the cardiology outpatient department (OPD) which could suggest aortic valve prolapse with AR in the aforesaid period before the infective endocarditis episode. In VSD, infective endocarditis does not develop on the high-pressure site; it develops on the low-pressure site like right ventricular side of IVS, undersurface of tricuspid or pulmonary valve, or right ventricular free wall. It is extremely rare to encounter the vegetation on the high-pressure zone of the restrictive perimembranous VSD, which includes the RCC and left ventricular side of the VSD. Paradoxically, we noted the vegetation on the high-pressure zone of a restrictive perimembranous VSD over the RCC, which is extremely rare to encounter in routine clinical practice. Although severe AR due to prolapse of the right and/or noncoronary cusps of the aortic valve is often seen in VSD, thereby increasing the risk of IE, our case did not reveal the same in the echocardiography done 1 year back. Additionally, during the 3-monthly follow-up in our outpatient department, prior to the infective endocarditis, she did not have any diastolic murmur of AR. Local hemodynamics operating behind the development of this vegetation over the RCC can be explained by Bernoulli's phenomenon. Across a small perimembranous VSD, turbulent blood stream rushes with high velocity, creating a negative pressure underneath the RCC. Bacteria traversing the aortic valve during ventricular systole fall over the belly of the RCC due to negative suction effect of the low pressure zone created by the turbulent high velocity jet across restrictive perimembranous VSD, form a vegetation and develop infective endocarditis of the RCC, develop a relatively larger colony due to presence of low pressure zone, destroy the valve, cause AR, and in some cases, valve may develop perforation or may become flail also. Our case illustrates paradoxical vegetation of RCC in a case of small restrictive VSD and also a unique presentation of left-to-right shunt with left-sided endocarditis, which is extremely rare to encounter in routine clinical practice. Hemodynamic principles always play a pivotal role behind the development of endocarditis including this case of small restrictive perimembranous VSD. The risk of infective endocarditis in patients with congenital heart disease is always a major concern. In adults with congenital heart disease, the incidence of infective endocarditis is as high as 11/100,000 patients compared with 1.5–6.0/100,000 patients in the general population., The risk of developing infective endocarditis substantially differs between unrepaired, repaired, and palliated category of congenital heart diseases. In cases of adult VSD, the risk of developing infective endocarditis is 20 times higher than that of normal population with approximate incidence of 2/1000 patient years. The incidence of infective endocarditis in VSD is 0.05%; that's why few pediatric cardiologists advice for prophylactic closure of restrictive VSD also, although it does not cause any derangement in quality of life in children except bearing a negligible risk of developing endocarditis as noted in our case. Shah et al. described a rare case of biventricular endocarditis in a case of small VSD having vegetation over the atrial surface of the mitral valve, ventricular surface of the aortic valve, right ventricular free wall, and under surface of the pulmonary valve in a 29-year-old immunocompetent male. Congenital heart diseases make patients more prone to infective endocarditis, and the risk of infective endocarditis is highest in tetralogy of Fallot cases followed by bicuspid aortic valve, coarctation of the aorta, and VSD cases. Frontera-Izquierdo and Cabezuelo-Huerta observed an incidence of infective endocarditis in 0.5% in 882 patients with isolated VSD. Otterstad et al. reported an approximate incidence of endocarditis in 15% in 109 patients with isolated VSD diagnosed after the age of 15 years (range 15–65). Pulmonary valve is the least commonly affected valve by infective endocarditis. Streptococcus species, including Streptococcus viridians, Streptococcus bovis, and Enterococci, are responsible for approximately 70% cases of native valve endocarditis. Staphylococcus species cause 25% of cases and usually result in an acute but aggressive course. In our case, Streptococcus viridians was the culprit organism. Small VSD presenting as isolated infective endocarditis of RCC is extremely rare to encounter in routine clinical practice as well as the left-sided endocarditis in a case of restrictive left to right shunt.
| Conclusion|| |
Our case illustrates isolated paradoxical vegetation over RCC in a case of small restrictive perimembranous VSD. Bernoulli's phenomenon creating negative pressure over the RCC due to turbulent blood jet across small VSD may be favoring the bacteria to settle down there to form a nidus and subsequent vegetation, and may be the plausible explanation behind this phenomenon. Local hemodynamics always governs both the beauty and ugly of nature.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]