Ruptured Sinus of Valsalva in a Patient undergoing Caesarean Section. Which Anesthetic would be preferable?

Introduction
The Valsalva sinus aneurysm is a rare cardiac anomaly due to a faulty fusion of the aortic tunica muscularis with the anulus fibrosus cordis. Although this type of aneurysm may appear in the context of collagen disorders such as the Marfan and Ehlers-Danlos syndromes, in most cases it has been found to be of congenital origin1.
Most studies show that the aneurysm originates from the right Valsalva sinus which ruptures into the right ventricle or atrium. This usually is not perceived by the patient unless it occurs in the third or fourth decade of life. Studies show that the haemodynamic alterations due to such an event are rather important .
There are few documented cases of ruptured sinus Valsalva aneurysms during pregnancy and even less information is available with reference to the anaesthetic management of these patients. The present report deals with a primiparous woman diagnosed with a sinus of Valsalva aneurysm ruptured into the right ventricle making an elective caesarean delivery necessary.
Case report
A thirty-year-old pregnant patient came to hospital with a sinus of Valsalva aneurysm ruptured into the right ventricle in the 11th week of gestation. Her only medical problem was this cardiac anomaly diagnosed during her childhood. Some episodes of dyspnea and palpitations were detected during her infancy but were not further investigated. During adolescence she reported having episodes of chest tightness that were not related to physical exercise. An echocardiogaphic study performed in her native country (Bolivia) recommended surgery which she refrained from. The previously described symptoms continued without deterioration between her adolescence and the beginning of her gestation. The lack of data collected from her history required a cardiac evaluation which was performed in the 12th week of her pregnancy. She did not complain of dyspnea, orthopnea, nocturnal paroxysmal dypsnea, nycturia, and syncope. During physical exercise, signs of cardiac failure were not observed. Auscultation revealed normorhythmia as well as systolic and diastolic flows. Precordial auscultation revealed a fremitus. Blood pressure was 110 over 50 with a heart rate of 68 beats per minute. A 12-lead ECG displayed a sinus rhythm, a prolonged PR interval, and an incomplete right bundle branch block. Transthoracic echocardiography (Figure 1) revealed an aneurysmatic dilatation of the right sinus of Valsalva with a fistula to the right ventricle. The anatomy of the aortic root was found to be normal. The normokinetic left and right ventricles were slightly dilated, both with normal ventricular function. Slight to moderate pulmonary hypertension was detected. The mitral and pulmonary valves were normal but there was a tricuspid valve insufficiency of I-II/IV degree. An echo-colour-Doppler (Figure 2) revealed a fistula between the aortic root and the right ventricle with prominent flow between both structures. However, this left-to-right shunt may have been overestimated due to a diameter increase of the right ventricle’s outflow tract presumably resulting from a normal dilation of the pulmonary artery during pregnancy.
In the course of her pregnancy, the patient was followed meticulously to reach a term gestation. Two additional echocardiographic studies in the 12th and 24th week demonstrated no significant changes. In the 36th week of pregnancy the patient complained of chest tightness, rest dyspnea, and orthopnea. Echocardiography revealed no signs of ventricular deterioration nor an increase in pulmonary artery pressure. It was finally decided to perform a caesarean section in the 38th week of her gestation.
Following peripheral intravenous access, endocarditis prophylaxis was given according to our hospital protocol consisting of intravenous ampicillin 1g and gentamicin 80mg one hour prior to surgery. Monitoring consisted of an ECG, pulse oximetry, and left radial artery cannulation for continuous blood pressure measurements. A spinal anaesthetic with a 25G pencil-point needle (Withacre®) was performed at the L3-L4 interspace using 9 mg of hyperbaric bupivacaine 0.5%. Cold test revealed a dermatomal level of T5. Surgery without complications lasted approximately 45 minutes with an estimated blood loss of 800 ml. A 2.750g female infant was born with Apgar scores of 9, 10, 10 after one, five, and ten minutes, respectively.
Intraoperatively, the patient showed overall haemodynamic and ventilatory stability. On the 4th postoperative day, echocardiography was repeated which proved to be no different from previous ones. The patient was discharged on the 5th postoperative day.
Discussion
This case reports on a 30 year old primiparous woman diagnosed with an aneurysm of the right sinus of Valsalva fistulating to the right ventricle. In addition, the patient suffered from a moderate pulmonary hypertension and a tricuspid valve I-II/IV insufficiency. In the initial phase of her pregnancy, she experienced occasional dyspneic episodes, chest tightness, and atypical chest pain. In the course of her gestation, orthopnea developped, chest tightness and pain became more frequent and dyspnea was seen even at rest. Elective caesarean section in the 38th week under spinal anaesthesia was uneventful and the newborn´s Apgar scores were within normal range.
The aneurysm of sinus of Valsalva involves less than 1% of all congenital cardiac anomalies. It is more common in males and among the Asian population. The aneurysm can remain intact or may rupture causing important haemodynamic changes such as an acute overload of the right ventricle eventually leading to right pump failure. Even if the aneurysm does not rupture, it may still cause an obstruction of the outflow tract, as well as endocarditis, thromboembolism, or fascicular block. Congestive heart failure, arrhythmias, heart tamponade, ischemia, or even sudden cardiac death, all have been described2. There are only few data on the development of this anomaly.
Echocardiographic studies and surgical findings seem to correlate well. Other tests such as angiography and nuclear magnetic resonance can be helpful . Pregnancy brings about cardiovascular changes that can be risk factors in this anomaly. Women who suffer from additional pulmonary hypertension are considered at high risk during pregnancy due to a significant increase in total blood volume and cardiac output. This increase can even be of further risk if there is a left-to-right shunt as in the present report .
A literature search yielded one similar case report describing a patient with the same anomaly ruptured into the right ventricle without pulmonary hypertension in the first phase of her second pregnancy . Both her gestations lead to a vaginal delivery without complications. However, this report did not mention the potential haemodynamic alterations during labour. A multidisciplinary consensus in the present case report suggested an elective caesarean section in the 38th week of gestation. The most important goal was to avoid potential worsening of the patient’s basal cardiac situation as she reached the end of her pregnancy.
There were several reasons to administer a spinal anaesthetic. Comparing regional with general anaesthesia in caesarean delivery, a described decrease in maternal mortality after centroneuraxis blockade was considered the most important reason , .
According to the Cochrane Central Register both spinal and epidural anaesthesia seem to be associated with less intraoperative bleeding with accordingly less need for perioperative blood transfusions as compared to general anaesthesia . In this meta-analysis of 16 trials (more than 1500 caesarean deliveries under spinal and epidural anaesthesia), no anaesthetic technique proved to be superior8. Cochrane Central Register proved that an effective neural blockade for caesarean section can be achieved with both techniques; no differences were demonstrated regarding the anaesthetic effectiveness, the failure rate, side effects, the need for additional intraoperative analgesia, conversion to general anaesthesia, maternal satisfaction, or an increased necessity for neonatal supervision after birth8. The most prominent advantage of the spinal anaesthetic was its shorter onset and depth of blockade, yet there was a higher probability of sudden hypotension which could be treated easily8.
The patient displayed a left-to-right shunt with moderate pulmonary hypertension and without significant valvular heart disease. The priority was to avoid an increase of systemic and pulmonary vascular resistance as well as to maintain an adequate volume preload. With these arguments, both spinal and epidural anaesthesia were considered safe options. A spinal anaesthetic was eventually selected and administered successfully.


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