Flexible fibre optic bronchoscopy as angioscope to ascertain completeness of pulmonary embolectomy: surgery for pulmonary embolism—how I do it

Abstract

Rarely pulmonary embolectomy has also been used as a salvage procedure for acute right ventricle (RV) dysfunction following acute pulmonary embolism (APE). Complete surgical removal of thromboembolus in acute pulmonary thromboembolism is an essential pre-requisite for good outcome. Complete clearance of thromboembolic load from pulmonary arterial tree is difficult to assess intraoperatively. We hereby describe the use of flexible fibre optic bronchoscope (FFB) as angioscope to visualise the pulmonary arterial tree intraoperatively. Angioscopy ascertains the complete clearance up to subsegmental level after thromboembolectomy and aids in the removal of residual thrombus or embolus. Herein, we describe a case series of two patients, where FFB was used as angioscope during surgery for APE.

Case reports

Case 1

Sixty-six-year-old male type II diabetic was referred to us with a diagnosis of renal cell carcinoma (RCC) of the left kidney invading into inferior vena cava (IVC). Computed tomography (CT) revealed a 16 × 14 × 11-cm mass in the left kidney with necrotic areas invading the surrounding Gerota’s fascia extending into the left renal vein and IVC (Fig. 1a). His duplex Doppler of both lower limb veins did not reveal any evidence of deep vein thrombosis (DVT). Pre-operative coronary angiogram revealed coronary artery disease (CAD) needing coronary artery bypass grafting (CABG) to left anterior descending (LAD), obtuse marginal (OM) and right coronary arteries (RCA). Echocardiography revealed good left ventricular function with no other valvular abnormalities and normal pulmonary artery pressures—right ventricle systolic pressure (RVSP) of 45 mmHg and no regional wall motion abnormality (RWMA). He did not have any distant metastases.

Fig. 1.

a CT scan of the abdomen showing the renal tumour. b LPA embolectomy specimen. c Suction port in FFB sucking the clot from PA. d SVG after completion of distal anastomosis. Legend of abbreviations: FFB, flexible fibre optic bronchoscopy

He was planned for concomitant left radical nephrectomy and CABG. Trans oesophageal echo (TEE) probe was introduced after anaesthetic induction to monitor cardiac status and IVC thrombus. Through a midline laparotomy, the oncosurgeon approached the renal mass first. The infra-renal IVC, left and right renal artery and vein were looped. During the mobilisation of left kidney, we suddenly saw disappearance of the IVC thrombus in the TEE monitor. The tumour had embolised into the pulmonary artery (PA) resulting in acute hemodynamic deterioration. This was managed with Inj milrinone 0.5 mic/kg/min and Inj noradrenaline 0.05 mic/kg/min and hemodynamics were stabilised. As the hemodynamics improved with inotrope itself, immediate cardiopulmonary bypass (CPB) was not instituted to reduce the CPB time eventually. Left nephrectomy was completed. Haemostasis was confirmed and the abdomen was closed. By a midsternotomy approach and after systemic heparinistaion (3 mg/kg), CPB was established with aorto bicaval cannulation and he was cooled to 20 °C nasal temperature. At 20 °C, the aorta was cross clamped, caval tapes were snared and blood cardioplegia was administered. After cardiac arrest, total circulatory arrest (TCA) was established and patient drained. Main PA was opened and extended up to LPA. The IVC thrombus (Fig. 1b) which had embolised to LPA was gently removed with ovum forceps. Flexible fibre optic bronchoscope (FFB) (Olympus Evis Exera© paediatric III with 3.0 mm diameter) was passed to the LPA, as an angioscope and residual bits of thrombi were sucked out (Fig. 1c) from LPA right up to the tertiary branches after saline irrigation through the irrigation port of FFB. Completeness of embolectomy from LPA was reconfirmed by FFB. As the right PA (RPA) was not clearly visualised in TEE, FFB was directed to RPA, which revealed significant emboli in RPA distally. Hence, an additional incision was made in the RPA between the superior vena cava and ascending aorta. Embolectomy performed from RPA, once again aided by FFB through the RPA arteriotomy to aid the removal of small thrombi and to confirm the completeness of embolectomy. Circulation resumed and pulmonary arteriotomies repaired with 5–0 poly propylene. Rewarming commenced. During rewarming phase, CABG was performed with three reversed saphenous vein grafts to LAD, OM and RCA (Fig. 1d). The CPB, aortic cross clamp (ACC) and TCA times were 185, 136 and 35 min respectively with a reperfusion period of 10 min. The patient was weaned off CPB uneventfully. TEE confirmed no residual embolus in the IVC-right atrium (RA) junction which enabled us to prevent an unnecessary exploration in the IVC-RA junction through the right atriotomy as well as additionally opening up IVC in the abdomen. He was extubated on 1st post-operative day (POD) and had an uneventful post-operative recovery with no neurological deficit. His post-operative echo showed RVSP of 40 mmHg and no new RWMA. He was discharged home on 7^th POD on oral anticoagulation. During follow-up @ 6 months, he has remained in New York Heart Association (NYHA) class I. On follow-up, anti-coagulation was stopped as computed tomography pulmonary angiogram (CTPA) showed no evidence of pulmonary embolism or thrombus.

Case 2

A 40-year-old male, a chronic smoker, was hospitalised under Cardiology services of our Hospital with acute onset dyspnoea NYHA III of 3-day duration which rapidly worsened to NYHA IV. Echo cardiogram revealed moderate right ventricle (RV) dysfunction with tricuspid annular plane systolic excursion (TAPSE) of 13 mm with clot in proximal RPA and LPA and he was diagnosed with acute pulmonary embolism (APE). CTPA showed thrombus confined to bilateral proximal PA (Fig. 2a). Lower limb venous Doppler revealed DVT of the left common femoral and iliac veins. He was thrombolysed with urokinase in a dose of 4400 IU/kg as a loading dose followed by 4400 IU/kg/hr for 12 h. Post thrombolysis, there was only partial resolution of symptoms with persisting RV dysfunction (TAPSE—10 mm). He continued to be oxygen and non-invasive ventilation (NIV) dependent even after 3 days post thrombolysis. He was planned for urgent high-risk pulmonary thromboembolectomy. Surgery was by midsternotomy, aorto bicaval cannulation and systemic hypothermia. At 20 °C, the aorta was cross clamped and blood cardioplegic arrest was obtained. TCA was established and patient was drained. Main PA was opened and extended up to LPA. The embolus (Fig. 2b) from LPA was gently removed with ovum forceps. FFB was passed as an angioscope to the LPA and residual bits of thrombi were sucked out from LPA. Completeness of embolectomy from LPA was confirmed by FFB. An additional incision was made in the RPA between superior vena cava and ascending aorta. Embolectomy was performed from RPA, once again aided by FFB. Circulation resumed and the LPA was repaired with a bovine pericardial patch (Fig. 2c) and RPA directly repaired with 5–0 polypropylene suture. The TCA time was 30 min with a reperfusion period of 10 min. FFB confirmed no residual thrombi and intact endothelium. He was ventilated for 24 h and extubated on 1^st POD. On 2^nd POD, IVC (Cook celect plus© 30 × 50 mm retrievable type) filter implantation was performed by intervention radiologist in view of left lower limb vein DVT. On discharge, RV function significantly improved (TAPSE 16 mm). On last follow-up at 3 months, patient is in NYHA II with saturation of 98% in room air. His echo showed RVSP of 50 mmHg and he is on warfarin long term.

Fig. 2.

a CTPA showing RPA and LPA thrombus. b Post op embolectomy specimen organised in the PA branches. c Intra op picture of LPA patch closure. Legend of abbreviations: MPA, main pulmonary artery; LPA, left pulmonary artery; RPA, right pulmonary artery

Discussion

At the outset, surgery for APE is rare because of (1) missed diagnosis, (2) successful thrombolysis in most cases and (3) extremely moribund patient who often fails to reach the operating table even if referred. Indications for surgery in APE include (1) failed thrombolysis (as in our case no. 2) and (2) acute hemodynamic compromise due to massive APE (as in our case no. 1) [1]. Though the extent of thromboembolism is well visualised by pre op CTPA images, complete and thorough removal of thromboembolic load in pulmonary arterial tree intraoperatively is a technical challenge. Successful surgical outcome in APE depends on complete clearance of pulmonary arterial tree and not leaving behind any residual disease [1].

Though choledoscope as an angioscope has been described in medical literature [2] as early in 1989, usage of angioscope as an aid intraoperatively during pulmonary embolectomy is infrequently reported [3, 4]. FFB has not been reported as an angioscope to visualise pulmonary arterial tree so far in literature. We used it in our first case report of acute pulmonary embolism out of necessity as we were unsure of completeness of removal of embolus intraoperatively. Encouraged by the result obtained with our first case of APE, we used FFB as angioscope in subsequent cases as an aid to confirm clearance of pulmonary arterial tree. Intraoperative angioscope is both diagnostic in detecting residual disease and therapeutic in sucking out debris and clots after saline irrigation. Choledoscopes which are described in literature [5] as angioscopes are not readily available in most cardiothoracic surgical theatres, whereas FFB is ubiquitous and most cardiothoracic surgeons will be adept in using this as angioscope.

FFB is often only disinfected during bronchoscopy using glutaraldehyde. There is a word of caution though. If FFB is to be used as angioscope, it needs to be sterilised in an ENDOCLENS© machine which contains ortho-pthaldehyde (2%) and isopropyl alcohol as disinfectants. The machine washes the scopes for a period of 20 min in a total of three cycles each lasting for 7 min [6]. Following this, the FFB is taken inside the operation theatre for performing the procedure.

FFB (paediatric) with a diameter of 3 mm allows for easy suctioning and visualisation of the distal vasculature up to the subsegmental vessels, which helps to suck out any residual debris or clot, thereby achieving complete clearance of pulmonary vasculature. FFB as an angioscope can be a useful adjunct during surgery for APE. Angioscopy helps in diagnosing residual thromboembolic disease in pulmonary arterial tree as well as a therapeutic tool in clearing residual thromboembolic material and debris by saline irrigation and suctioning.

Generally for APE, TCA is not required. However, the usage of TCA in case no. 1 was in anticipation of isolation of IVC from circulation if necessary for easier retrieval of clot, and in case no. 2, TCA was employed for better visualisation to provide a blood less field as we were unsure of the redundant adherence of the thrombus to the vessel wall post failure of thrombolysis. Van Putte et al. [7] described the usage of intermittent TCA for surgery of APE in order to provide a blood less field.

Another technique which people use in surgery for APE is retrograde pulmonary perfusion through the pulmonary veins. This technique is helpful especially to flush out clots in the pulmonary arterial tree that is beyond visualisation. Though this technique has many advantages [8], there is always a risk of pulmonary edema and over flooding if there is too much perfusion pressure [9]. We opine that this procedure is quite time consuming and also cumbersome with separate perfusion cannulae into the pulmonary vein and left atrium, which can also be a source of bleeding and can cause pulmonary venous endothelial damage. Compared to that, FFB is quite simple and less time consuming and easily aspirates clots from the pulmonary vascular tree beyond the scope of direct visualisation. There is no literature data available comparing the two techniques in a head to head basis for APE. Some of the other techniques available for washing out the clots are Fogarty balloon pulmonary embolectomy, squeezing or gently massaging the lungs to extract the clots. Kawahito et al. [3] describe their technique of Fogarty embolectomy with irrigation using cold saline through the irrigation port. There is a risk of fluid overload in their technique which might need filtration during CPB. Also, one has to be careful while carefully inflating the Fogarty balloon and retrieving the clots as there is a possibility of injuring the pulmonary arterial vascular tree if there is excessive manipulation during this technique.

Conclusion

Herein, we propose a simple yet easy surgical innovation of FFB being used as an adjunct to ensure the completeness of pulmonary embolectomy in APE. There are only few anecdotal reports of its usage for the same. Hence, we believe that this technique can be safely used both as diagnostic and therapeutic purpose during surgery for APE so that complete clearance is assured which can be confirmed on table.

Funding

None.

Declarations

Ethical approval.

Obtained.

Informed consent

Obtained.

Conflict of interest

The authors declare no competing interests.