Case Report
Cardiac surgery during pregnancy: Continuous fetal monitoring using umbilical artery Doppler flow velocity indices Manisha Mishra, Ravindra Sawhney, Anil Kumar, Kumar Ramesh Bapna1, Vijay Kohli1, Harpreet Wasir1, Naresh Trehan1 Departments of Cardiaothoracic and Vascular Anesthesiology, 1Departments of Cardiaothoracic and Vascular Surgery, Medanta The Medicity, Gurgaon, Haryana, India
ABSTRACT
Received: 27‑04‑13 Accepted: 08‑10‑13
The fetal death rate associated with cardiac surgery with cardiopulmonary bypass (CPB) is as high as 9.5‑29%. We report continuous monitoring of fetal heart rate and umbilical artery flow‑velocity waveforms by transvaginal ultrasonography and their analyses in relation to events of the CPB in two cases in second trimester of pregnancy undergoing mitral valve replacement. Our findings suggest that the transition of circulation from corporeal to extracorporeal is the most important event during surgery; the associated decrease in mean arterial pressure (MAP) at this stage potentially has deleterious effects on the fetus, which get aggravated with the use of vasopressors. We suggest careful management of CPB at this stage, which include partial controlled CPB at initiation and gradual transition to full CPB; this strategy maintains high MAP and avoids the use of vasopressors. Maternal and fetal monitoring can timely recognize the potential problems and provide window for the required treatment. Key words: Cardiac surgery; Cardiopulmonary bypass; Fetal monitoring; Mitral valve disease; Pregnancy
INTRODUCTION
Access this article online
Website: www.annals.in PMID: *** DOI: 10.4103/0971-9784.124141 Quick Response Code:
The incidence of heart disease in pregnant women ranges from 1% to 4%, accounting for 10‑15% of maternal deaths, which is similar to the non‑pregnant women undergoing similar cardiac procedures on cardiopulmonary bypass (CPB). [1] The fetal mortality in such patients has remained unchanged at 9.5‑29%, with an average of 19% over the past 25 years. [1‑3] Arguably, perioperative management of pregnant women undergoing cardiac surgery with CPB should take the well‑being of both mother and fetus into consideration; fetal and maternal monitoring during cardiac surgery with CPB can allow the greatest control of risk in the pregnant patient. Although, successful valve repair and replacements during pregnancy have been reported.[4‑6] Most of these studies are case reports, at times organized as literature
review.[4] This report documents the procedure details and outcome of cardiac surgery in two pregnant women in second trimester of pregnancy with rheumatic mitral valve disease at our tertiary care referral hospital. CASE REPORTS Case 1 A 33‑year‑old gravida III, para II was admitted to our hospital at 16‑week gestation with palpitation and acute shortness of breath (NYHA Class IV). Her medical history revealed history of balloon mitral valvulotomy (BMV) at the age of 21 years for rheumatic mitral valve stenosis (MS). The MS was diagnosed during first pregnancy when she became symptomatic at 20 weeks gestation. On examination, she was found to be in atrial fibrillation with fast ventricular rate of 146 beats/min. Transthoracic echocardiography revealed
Address for correspondence: Dr. Manisha Mishra, D-2, Front Portion, SF, Kalindi Colony, New Delhi-110065, India. E-mail: [email protected]
46
Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
a thickened, heavily calcified stenosed mitral valve with an area of 0.6 cm2, moderately severe eccentric jet of mitral regurgitation and a clot in left atrial (LA) appendage, which ruled out BMV as a treatment option. Hence, mitral valve repair/replacement was the treatment of choice. Obstetrical examination revealed positive fetal viability and an ultrasound demonstrated normal development consistent with the gestational age of 16 weeks. Case 2 A 26‑year‑old gravida II, para I was admitted with complaints of breathlessness on exertion (NYHA Class III) at 17 weeks of gestation. She had undergone BMV 3 years ago during her first pregnancy when she went into congestive cardiac failure at 24 weeks gestation. At present, she was in normal sinus rhythm with a heart rate of 112 beats/min. Echocardiography demonstrated severe MS with an area of 0.8 cm 2, moderate tricuspid valve regurgitation and moderate pulmonary artery hypertension. Surgery was the only option at this stage of gestation. Both families were counseled about the risks of the procedure. Progesterone 100 mg intramuscular was started a day prior to surgery. Services of a dedicated obstetrician and a ultrasonologist were ensured inside the operating room to monitor fetal heart rate (FHR) and interpret umbilical artery flow‑velocity waveform throughout the procedure. As both cases are similar in their clinical profile and surgery was performed within an interval of 2 months following similar technique, hence the anesthetic and CPB management are being discussed together. Baseline FHR and rhythm were recorded before induction of anesthesia. Anesthesia was induced with etomidate and fentanyl; vecuronium 0.1 mg/kg was administered to facilitate endotracheal intubation. Anesthesia was maintained with O2: Air mixture (50:50), isoflurane 1‑1.5%, fentanyl 5 µg/kg, and incremental doses of vecuronium. During surgery, the patients were monitored with radial artery pressure, a pulmonary artery catheter placed through the right internal jugular vein, and transesophageal echocardiography. Additionally, FHR and umbilical artery flow‑velocity waveforms were continuously monitored by transvaginal ultrasonography (Siemens, ACUSON X300™ ultrasound system and transvaginal ultrasound probe 9‑14 MHz) and analyzed in relation to events of the CPB. Heparin, 4 mg/kg was given for anticoagulation and activated clotting time was maintained at >550 s. [4] CPB management was standard and included aortic and two separate Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
vena cava cannulation, crystalloid prime, Capiox sx 18R hollow fiber membrane oxygenator (Terumo cardiovascular systems Inc., Elkton, MD 21921) and 38 µ arterial filter (AFFINITY®, Medtronic, Inc. MN 55432). Initially, to avoid precipitous decrease in mean arterial pressure (MAP), partial CPB with a single venous cannula was established then gradually, after ensuring hemodynamic stability, full CPB was established. Thereafter, aorta was clamped, during clamping myocardium was protected by topical cooling with ice slush and hyperkalemic, cold (4°C) blood cardioplegia infused into the aortic root at 10 ml/kg body weight at 20 min interval. Systemic normothermia at 35‑36°C was maintained. The MAP during CPB was aimed to be maintained at 70‑80 mmHg and the CPB flow was kept between 2 and 2.5 L/m2/min. If MAP was lower than 70 mmHg; initially, the CPB flow was increased, vasoconstrictors were used sparingly. Hematocrit was maintained between 25-30% and PaO2 at 400 mmHg. Pulsatile flow was maintained throughout CPB, using Terumo Sarns™ Modular Perfusion System 8000 (Terumo CVS‑Ann Arbor MI 48103). Case 1 underwent mitral valve replacement with 27 mm (Epic™ St. Jude Medical Minnesota 55117 USA) bioprosthesis along with removal of LA clot and ligation of LA appendage. Case 2 underwent mitral valve replacement with similar 25 mm bioprosthesis along with tricuspid valve repair. Aortic cross clamp time was 30 min in Case 1 and 48 min in Case 2. After unclamping of the aorta, cardiac activity resumed after a single defibrillation with 10 joules in Case 1, whereas it returned spontaneously in Case 2. Both the patients were weaned from CPB without any inotropic support; the CPB times were 38 min and 55 min, respectively [Table 1]. After the patients were weaned off CPB, protamine was administered and hemostasis completed. In both the cases after bypass, the FHR gradually increased (over 15 min) to 135‑150 beats/min. Patients were shifted to intensive care unit and continuous maternal and fetal monitoring was continued. Patients were extubated 6 h and 8 h after surgery. Post‑operative course was uneventful. MAP, FHR and umbilical artery Doppler flow‑velocity indices at the initiation of CPB and during CPB Progressive deceleration of FHR was noted with the onset of CPB in both the cases [Figure 1]. In Case 1, the initiation of CPB was accompanied by fetal bradycardia, the FHR decreased to 80 beats/min; the CPB flow was increased to 3.5 L/m2/min, which led to an increase in FHR to > 100/min. The FHR recovered completely within 15 min of separation from CPB. In Case 2, 47
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
Table 1: Summary of cardiac procedures done on both pregnant patients Variables
Case 1
Case 2
Maternal Age (yrs)
33
26
BSA (m²)
1.7
1.4
Fetal gestation (wks)
16
15
Diagnosis
RHD with Mitral stenosis and LA Clot
RHD with mitral stenosis and Tricuspid Regurgitation
Indication for surgery
Cardiac failure
Symptomatic severe MS
Surgical procedure
MVR
MVR+Tricuspid repair
Aortic clamp time (min)
30
48
CPB time (min)
38
55
Lowest Temperature
35.2° C
35.5° C
Hospital stay
6 days
10 days
Fetal outcome
Term, normal baby
Fetal demise
Maternal outcome
Good
Good
RHD: Rheumatic heart disease, MVR: Mitral valve replacement, MS: Mitral stenosis, LA: Left atrium
the FHR decreased to 40 beats/min after initiation of CPB; this decrease in FHR was accompanied by a fall in MAP to 46 mmHg and responded transiently to an increase in pump flow rates. The MAP increased in a few minutes to 65 mmHg after the administration of ephedrine 5 mg, yet the FHR did not increase above 60 beats/min on CPB. Hydrocortisone 100 mg was administered and infusion of nitroglycerin was started empirically in the hope of avoiding a further decrease in FHR due to placental vasoconstriction leading to fetal hypoxia. The FHR recovered gradually until completion of operation. The FHR and Doppler flow velocitymetry indices of umbilical artery flow were analyzed in order to diagnose fetal hypoxia and/or acidosis, which are presumed to be associated with elevated placental vascular resistance. A thorough analysis of the Figures 2a‑d. substantiates the above presumption. In Case 2, At the initiation of CPB when the MAP decreased to 46 mmHg, the Doppler flow velocity profile showed absence of diastolic flow and fetal bradycardia [Figure 2a], the diastolic flow gradually appeared over 5 min as the MAP increased, though with vasopressors, but fetal bradycardia persisted [Figure 2b]. The umbilical artery flow, both systolic and diastolic improved further after nitroglycerin infusion [Figure 2c]. At 30 min on CPB, the FHR again decreased to 40 beats/min and once again, the diastolic flow disappeared, despite a MAP of 70 mmHg [Figure 2d]. The flow‑velocity indices went 48
Figure 1: Graphic depiction of fetal and maternal vital signs during surgery
up, the resistive index (RI) increased to 1.96 and the pulsatility index (PI) was 6.2 [Figure 3], which indicates an increased utero‑placental resistance. Interestingly, the arterial blood gases remained normal throughout the CPB and did not indicate any problem with the fetal circulation. Outcome of pregnancy Case 1 recovered uneventfully and was discharged from the hospital on the 6 th post‑operative day. Serial fetal ultrasounds revealed a normal fetus. She underwent a full term normal vaginal delivery at 38 weeks gestation and delivered a healthy normal baby. The Case 2 had normal FHR and fetal movements for the first four post‑operative days. On the 5th post‑operative day, FHR could not be located and fetal demise was detected, which was followed by spontaneous expulsion of fetus. DISCUSSION Cardiovascular changes during pregnancy are usually well tolerated in healthy women. However, 1‑4% of women of childbearing age have some degree of concomitant heart disease and they may present with compromised cardiac function.[1] The CPB induces a non‑physiologic hemodynamic state that can adversely affect the mother and the fetus during cardiac surgery.[3,7] The CPB is accompanied by alterations in the cellular and protein components of the blood. Apart from hemodilution and coagulation protein changes, activation of immune responses, particulate and air embolism and hypotension during CPB further add to the deleterious effects of CPB.[3,4] These changes are relatively well tolerated by the mother, to the extent Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
Figure 2a: Umbilical artery Doppler flow velocity profile in Case 2. The Doppler flow velocity profile showed bradycardia with absence of diastolic flow immediately at the initiation of cardiopulmonary bypass, mean arterial pressure was 46 mmHg
Figure 2b: Umbilical artery Doppler flow velocity profile in Case 2. After 5 min gradual appearance of diastolic flow, as the mean arterial pressure came up to 75 mm Hg with vasopressors, but fetal bradycardia persisted
Figure 2c: Umbilical artery Doppler flow velocity profile in Case 2. The umbilical artery flow, both systolic and diastolic improved further after nitroglycerine infusion
Figure 2d: Umbilical artery Doppler flow velocity profile in Case 2. At 30 min of cardiopulmonary bypass the fetal bradycardia, 40 beats/min and the absent diastolic flow persisted despite a mean arterial pressure of 70 mm-Hg
Figure 3: Graphic demonstration of changes in resistive index and pulsatility index of umbilical artery flow during surgery
that the maternal mortality rate associated with CPB in pregnant women is similar to that in non‑pregnant Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
women who undergo similar cardiac procedures on CPB.[7] Cardiovascular maternal morbidity and mortality during pregnancy correlate strongly with maternal functional status.[8,9] Four major risk factors predict adverse maternal outcomes: (1) History of transient ischemic attack, stroke, or arrhythmia. (2) NYHA heart failure classification of three or four before onset of pregnancy (3) left‑heart obstruction‑mitral valve area
Cardiac surgery during pregnancy: Continuous fetal monitoring using umbilical artery Doppler flow velocity indices Manisha Mishra, Ravindra Sawhney, Anil Kumar, Kumar Ramesh Bapna1, Vijay Kohli1, Harpreet Wasir1, Naresh Trehan1 Departments of Cardiaothoracic and Vascular Anesthesiology, 1Departments of Cardiaothoracic and Vascular Surgery, Medanta The Medicity, Gurgaon, Haryana, India
ABSTRACT
Received: 27‑04‑13 Accepted: 08‑10‑13
The fetal death rate associated with cardiac surgery with cardiopulmonary bypass (CPB) is as high as 9.5‑29%. We report continuous monitoring of fetal heart rate and umbilical artery flow‑velocity waveforms by transvaginal ultrasonography and their analyses in relation to events of the CPB in two cases in second trimester of pregnancy undergoing mitral valve replacement. Our findings suggest that the transition of circulation from corporeal to extracorporeal is the most important event during surgery; the associated decrease in mean arterial pressure (MAP) at this stage potentially has deleterious effects on the fetus, which get aggravated with the use of vasopressors. We suggest careful management of CPB at this stage, which include partial controlled CPB at initiation and gradual transition to full CPB; this strategy maintains high MAP and avoids the use of vasopressors. Maternal and fetal monitoring can timely recognize the potential problems and provide window for the required treatment. Key words: Cardiac surgery; Cardiopulmonary bypass; Fetal monitoring; Mitral valve disease; Pregnancy
INTRODUCTION
Access this article online
Website: www.annals.in PMID: *** DOI: 10.4103/0971-9784.124141 Quick Response Code:
The incidence of heart disease in pregnant women ranges from 1% to 4%, accounting for 10‑15% of maternal deaths, which is similar to the non‑pregnant women undergoing similar cardiac procedures on cardiopulmonary bypass (CPB). [1] The fetal mortality in such patients has remained unchanged at 9.5‑29%, with an average of 19% over the past 25 years. [1‑3] Arguably, perioperative management of pregnant women undergoing cardiac surgery with CPB should take the well‑being of both mother and fetus into consideration; fetal and maternal monitoring during cardiac surgery with CPB can allow the greatest control of risk in the pregnant patient. Although, successful valve repair and replacements during pregnancy have been reported.[4‑6] Most of these studies are case reports, at times organized as literature
review.[4] This report documents the procedure details and outcome of cardiac surgery in two pregnant women in second trimester of pregnancy with rheumatic mitral valve disease at our tertiary care referral hospital. CASE REPORTS Case 1 A 33‑year‑old gravida III, para II was admitted to our hospital at 16‑week gestation with palpitation and acute shortness of breath (NYHA Class IV). Her medical history revealed history of balloon mitral valvulotomy (BMV) at the age of 21 years for rheumatic mitral valve stenosis (MS). The MS was diagnosed during first pregnancy when she became symptomatic at 20 weeks gestation. On examination, she was found to be in atrial fibrillation with fast ventricular rate of 146 beats/min. Transthoracic echocardiography revealed
Address for correspondence: Dr. Manisha Mishra, D-2, Front Portion, SF, Kalindi Colony, New Delhi-110065, India. E-mail: [email protected]
46
Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
a thickened, heavily calcified stenosed mitral valve with an area of 0.6 cm2, moderately severe eccentric jet of mitral regurgitation and a clot in left atrial (LA) appendage, which ruled out BMV as a treatment option. Hence, mitral valve repair/replacement was the treatment of choice. Obstetrical examination revealed positive fetal viability and an ultrasound demonstrated normal development consistent with the gestational age of 16 weeks. Case 2 A 26‑year‑old gravida II, para I was admitted with complaints of breathlessness on exertion (NYHA Class III) at 17 weeks of gestation. She had undergone BMV 3 years ago during her first pregnancy when she went into congestive cardiac failure at 24 weeks gestation. At present, she was in normal sinus rhythm with a heart rate of 112 beats/min. Echocardiography demonstrated severe MS with an area of 0.8 cm 2, moderate tricuspid valve regurgitation and moderate pulmonary artery hypertension. Surgery was the only option at this stage of gestation. Both families were counseled about the risks of the procedure. Progesterone 100 mg intramuscular was started a day prior to surgery. Services of a dedicated obstetrician and a ultrasonologist were ensured inside the operating room to monitor fetal heart rate (FHR) and interpret umbilical artery flow‑velocity waveform throughout the procedure. As both cases are similar in their clinical profile and surgery was performed within an interval of 2 months following similar technique, hence the anesthetic and CPB management are being discussed together. Baseline FHR and rhythm were recorded before induction of anesthesia. Anesthesia was induced with etomidate and fentanyl; vecuronium 0.1 mg/kg was administered to facilitate endotracheal intubation. Anesthesia was maintained with O2: Air mixture (50:50), isoflurane 1‑1.5%, fentanyl 5 µg/kg, and incremental doses of vecuronium. During surgery, the patients were monitored with radial artery pressure, a pulmonary artery catheter placed through the right internal jugular vein, and transesophageal echocardiography. Additionally, FHR and umbilical artery flow‑velocity waveforms were continuously monitored by transvaginal ultrasonography (Siemens, ACUSON X300™ ultrasound system and transvaginal ultrasound probe 9‑14 MHz) and analyzed in relation to events of the CPB. Heparin, 4 mg/kg was given for anticoagulation and activated clotting time was maintained at >550 s. [4] CPB management was standard and included aortic and two separate Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
vena cava cannulation, crystalloid prime, Capiox sx 18R hollow fiber membrane oxygenator (Terumo cardiovascular systems Inc., Elkton, MD 21921) and 38 µ arterial filter (AFFINITY®, Medtronic, Inc. MN 55432). Initially, to avoid precipitous decrease in mean arterial pressure (MAP), partial CPB with a single venous cannula was established then gradually, after ensuring hemodynamic stability, full CPB was established. Thereafter, aorta was clamped, during clamping myocardium was protected by topical cooling with ice slush and hyperkalemic, cold (4°C) blood cardioplegia infused into the aortic root at 10 ml/kg body weight at 20 min interval. Systemic normothermia at 35‑36°C was maintained. The MAP during CPB was aimed to be maintained at 70‑80 mmHg and the CPB flow was kept between 2 and 2.5 L/m2/min. If MAP was lower than 70 mmHg; initially, the CPB flow was increased, vasoconstrictors were used sparingly. Hematocrit was maintained between 25-30% and PaO2 at 400 mmHg. Pulsatile flow was maintained throughout CPB, using Terumo Sarns™ Modular Perfusion System 8000 (Terumo CVS‑Ann Arbor MI 48103). Case 1 underwent mitral valve replacement with 27 mm (Epic™ St. Jude Medical Minnesota 55117 USA) bioprosthesis along with removal of LA clot and ligation of LA appendage. Case 2 underwent mitral valve replacement with similar 25 mm bioprosthesis along with tricuspid valve repair. Aortic cross clamp time was 30 min in Case 1 and 48 min in Case 2. After unclamping of the aorta, cardiac activity resumed after a single defibrillation with 10 joules in Case 1, whereas it returned spontaneously in Case 2. Both the patients were weaned from CPB without any inotropic support; the CPB times were 38 min and 55 min, respectively [Table 1]. After the patients were weaned off CPB, protamine was administered and hemostasis completed. In both the cases after bypass, the FHR gradually increased (over 15 min) to 135‑150 beats/min. Patients were shifted to intensive care unit and continuous maternal and fetal monitoring was continued. Patients were extubated 6 h and 8 h after surgery. Post‑operative course was uneventful. MAP, FHR and umbilical artery Doppler flow‑velocity indices at the initiation of CPB and during CPB Progressive deceleration of FHR was noted with the onset of CPB in both the cases [Figure 1]. In Case 1, the initiation of CPB was accompanied by fetal bradycardia, the FHR decreased to 80 beats/min; the CPB flow was increased to 3.5 L/m2/min, which led to an increase in FHR to > 100/min. The FHR recovered completely within 15 min of separation from CPB. In Case 2, 47
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
Table 1: Summary of cardiac procedures done on both pregnant patients Variables
Case 1
Case 2
Maternal Age (yrs)
33
26
BSA (m²)
1.7
1.4
Fetal gestation (wks)
16
15
Diagnosis
RHD with Mitral stenosis and LA Clot
RHD with mitral stenosis and Tricuspid Regurgitation
Indication for surgery
Cardiac failure
Symptomatic severe MS
Surgical procedure
MVR
MVR+Tricuspid repair
Aortic clamp time (min)
30
48
CPB time (min)
38
55
Lowest Temperature
35.2° C
35.5° C
Hospital stay
6 days
10 days
Fetal outcome
Term, normal baby
Fetal demise
Maternal outcome
Good
Good
RHD: Rheumatic heart disease, MVR: Mitral valve replacement, MS: Mitral stenosis, LA: Left atrium
the FHR decreased to 40 beats/min after initiation of CPB; this decrease in FHR was accompanied by a fall in MAP to 46 mmHg and responded transiently to an increase in pump flow rates. The MAP increased in a few minutes to 65 mmHg after the administration of ephedrine 5 mg, yet the FHR did not increase above 60 beats/min on CPB. Hydrocortisone 100 mg was administered and infusion of nitroglycerin was started empirically in the hope of avoiding a further decrease in FHR due to placental vasoconstriction leading to fetal hypoxia. The FHR recovered gradually until completion of operation. The FHR and Doppler flow velocitymetry indices of umbilical artery flow were analyzed in order to diagnose fetal hypoxia and/or acidosis, which are presumed to be associated with elevated placental vascular resistance. A thorough analysis of the Figures 2a‑d. substantiates the above presumption. In Case 2, At the initiation of CPB when the MAP decreased to 46 mmHg, the Doppler flow velocity profile showed absence of diastolic flow and fetal bradycardia [Figure 2a], the diastolic flow gradually appeared over 5 min as the MAP increased, though with vasopressors, but fetal bradycardia persisted [Figure 2b]. The umbilical artery flow, both systolic and diastolic improved further after nitroglycerin infusion [Figure 2c]. At 30 min on CPB, the FHR again decreased to 40 beats/min and once again, the diastolic flow disappeared, despite a MAP of 70 mmHg [Figure 2d]. The flow‑velocity indices went 48
Figure 1: Graphic depiction of fetal and maternal vital signs during surgery
up, the resistive index (RI) increased to 1.96 and the pulsatility index (PI) was 6.2 [Figure 3], which indicates an increased utero‑placental resistance. Interestingly, the arterial blood gases remained normal throughout the CPB and did not indicate any problem with the fetal circulation. Outcome of pregnancy Case 1 recovered uneventfully and was discharged from the hospital on the 6 th post‑operative day. Serial fetal ultrasounds revealed a normal fetus. She underwent a full term normal vaginal delivery at 38 weeks gestation and delivered a healthy normal baby. The Case 2 had normal FHR and fetal movements for the first four post‑operative days. On the 5th post‑operative day, FHR could not be located and fetal demise was detected, which was followed by spontaneous expulsion of fetus. DISCUSSION Cardiovascular changes during pregnancy are usually well tolerated in healthy women. However, 1‑4% of women of childbearing age have some degree of concomitant heart disease and they may present with compromised cardiac function.[1] The CPB induces a non‑physiologic hemodynamic state that can adversely affect the mother and the fetus during cardiac surgery.[3,7] The CPB is accompanied by alterations in the cellular and protein components of the blood. Apart from hemodilution and coagulation protein changes, activation of immune responses, particulate and air embolism and hypotension during CPB further add to the deleterious effects of CPB.[3,4] These changes are relatively well tolerated by the mother, to the extent Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
Mishra: Cardiac surgery during pregnancy and umbilical artery flow‑velocity indices monitoring
Figure 2a: Umbilical artery Doppler flow velocity profile in Case 2. The Doppler flow velocity profile showed bradycardia with absence of diastolic flow immediately at the initiation of cardiopulmonary bypass, mean arterial pressure was 46 mmHg
Figure 2b: Umbilical artery Doppler flow velocity profile in Case 2. After 5 min gradual appearance of diastolic flow, as the mean arterial pressure came up to 75 mm Hg with vasopressors, but fetal bradycardia persisted
Figure 2c: Umbilical artery Doppler flow velocity profile in Case 2. The umbilical artery flow, both systolic and diastolic improved further after nitroglycerine infusion
Figure 2d: Umbilical artery Doppler flow velocity profile in Case 2. At 30 min of cardiopulmonary bypass the fetal bradycardia, 40 beats/min and the absent diastolic flow persisted despite a mean arterial pressure of 70 mm-Hg
Figure 3: Graphic demonstration of changes in resistive index and pulsatility index of umbilical artery flow during surgery
that the maternal mortality rate associated with CPB in pregnant women is similar to that in non‑pregnant Annals of Cardiac Anaesthesia Vol. 17:1 Jan-Mar-2014
women who undergo similar cardiac procedures on CPB.[7] Cardiovascular maternal morbidity and mortality during pregnancy correlate strongly with maternal functional status.[8,9] Four major risk factors predict adverse maternal outcomes: (1) History of transient ischemic attack, stroke, or arrhythmia. (2) NYHA heart failure classification of three or four before onset of pregnancy (3) left‑heart obstruction‑mitral valve area
