Keywords
pulmonary embolism - lung cancer treatment (surgery, medical) - thoracic surgery
Introduction
Thirty-day mortality of patients who developed venous thromboembolism or pulmonary
embolism (PE) after lung cancer surgery is approximately 5%.[1] This can be explained by preexistent and surgically induced reduction of lung function
and pulmonary vasculature. Furthermore, general thoracic patients often are in a fragile
medical condition with cardiac and other comorbidities.
Acute right heart failure (RHF) is the most frightened complication of PE and is caused
within minutes by pressure overload. These patients have a 2.4- to 3.5-fold increase
in mortality compared with those without acute RHF.[2] Multiple prognostic models are available to classify mortality risk such as the
(simplified) Pulmonary Embolism Severity Index (sPESI and PESI) which stratifies patients
by clinical parameters.[3]
Ultrasound-assisted thrombolysis (USAT) with EkoSonic endovascular system (Boston
Scientific Corporation, Marlborough, Massachusetts, United States) is a relatively
novel catheter-based reperfusion technique that can be used in PE patients at high
risk for complications with systemic thrombolysis.[4] Kucher et al reported that USAT was superior to heparin alone in reversing right
ventricle (RV) dilatation without an increase in bleeding complications in intermediate-risk
PE patients.[5] In the very particular setting of high-risk PE directly after major lung resections,
systemic thrombolysis is usually contraindicated. Nevertheless, USAT enables fast
recovery of RV function and could be a convenient alternative to systemic thrombolysis,
but experience is lacking.
Here, we report a clinical case of a female patient with breast cancer and pulmonary
squamous cell carcinoma who developed PE after video-assisted lobectomy and was successfully
treated with USAT despite pulmonary surgery the day before.
Case Description
In 2020, a 60-year-old female patient was transferred to our thoracic department after
diagnosis of breast cancer with a second nonsmall cell lung carcinoma (NSCLC) in the
left upper lobe. Comorbidities included obesity, asthma, chronic obstructive pulmonary
disease, hypertension, and active smoking with 40-pack years.
The staging revealed a right-sided triple-negative breast cancer without lymph node
metastasis. Endobronchial ultrasound of mediastinal lymph nodes was also negative,
but transbronchial needle aspiration revealed a second primary squamous NSCLC of the
left upper lobe. Brain metastasis was excluded by magnetic resonance imaging scan.
Resection of the left upper lobe for NSCLC before chemotherapy for breast cancer was
indicated in a multidisciplinary tumor board.
The patient underwent uncomplicated minimally invasive (left upper) lobectomy and
mediastinal lymphadenectomy in the setting of standard video-assisted thoracic surgery
with three ports. The final histopathological diagnosis confirmed the diagnosis and
showed a barely differentiated squamous cell carcinoma (G3, pT2a, pN0) according to
the staging system by the Union for International Cancer Control. The patient returned
to standard postoperative care and only slight hoarseness as a possible sign of recurrent
nerve paralysis was recognized. On the second postoperative day, the patient developed
syncope, dyspnea, and decrease of saturation to 73%. A computed tomography (CT) scan
revealed a large right-sided PE including the right upper and middle pulmonary arteries,
with additional thrombotic material in the right lower pulmonary artery ([Fig. 1]). Additionally, we observed impaired RV function and elevated brain natriuretic
peptide of 299 pg/mL.
Fig. 1 Computed tomography (CT) scan with contrast showing predominantly right-sided pulmonary
embolism and a left-sided status with post-upper lobe lobectomy.
Cardiopulmonary function rapidly decreased, and the patient was transported to the
intensive care unit (ICU) for invasive ventilation and therapeutic vasopressors. According
to the PESI, the patient was classified as high-risk patient (class 4 with 4–11% risk
of 30-day mortality) due to age, history of cancer, and decreased O2 saturation (73%). Therefore, a multidisciplinary Pulmonary Embolism Response Team
decision was made for EKOS reperfusion therapy.
On the same day, the patient was transferred to the operation room for catheter placement
and immediate initiation of local right-sided USAT reperfusion. Afterwards the patient
stabilized, and the use of vasopressors could be reduced. CT scan evaluation of the
PE after 2 days revealed good positioning of the EKOS catheter in the right pulmonary
branch and regress in PE material ([Fig. 2]). EKOS reperfusion was applied for 3 days and the total amount of administered alteplase
was 24 mg. RV function normalized, and we observed no bleeding complications. Four
days after PE, the patient was successfully extubated. The total ICU time was 12 days
due to delirium and the patient was transferred to the general ward of a local hospital
for further recovery and planning of neoadjuvant chemotherapy for breast cancer. Prophylactic
anticoagulation with factor Xa inhibitor apixaban was prescribed. Consultation with
the attending oncologist was conducted 6 months after discharge. The patient was alive,
received chemotherapy, had no residual complaints of PE, and no evidence for recurrent
nerve paralysis. Neoadjuvant chemotherapy for breast cancer was planned and given
in her local hospital. Follow-up after 12 months showed no adverse signs or recurrence
of malignancy.
Fig. 2 Computed tomography (CT) scan with contrast showing good positioning of the EKOS
catheter in the (lower) right pulmonary artery branch and regression of pulmonary
embolism after 2 days.
Discussion
Although literature on USAT for PE after surgery is scarce, our team has some experience
in the use of EKOS in postsurgical patients.[6] In these cases, low-dose USAT appeared to be a safe and reasonable therapy for early
postoperative PE. Retrospective analysis with small sample sizes reported controverse
clinical outcomes between USAT and other catheter-directed modalities.[7]
[8] We still use USAT because this is the technique that is best supported by clinical
trial data.[5]
[9]
Special about our case is that patients after lung resection for malignancy suffer
from already compromised pulmonary reserve and critical medical condition. Therefore,
PE is an independent marker of poor outcome in this specific patient group.[10] Reduction of pulmonary reserve depends on the extent of lung resection and can range
from small wedge resections up to pneumectomies. The latter is associated with more
advanced disease and higher mortality. Our case comprised a left upper lobectomy which
leaves higher pulmonary reserve than a pneumectomy. However, thrombolysis with USAT
was given directly into pulmonary circulation despite previous lung surgery and literature
on this specific case is very scarce.
Apart from rare reports on systemic thrombolysis for PE after lung resection surgery,
Lee at al described a case with PE 6 weeks after pneumectomy that was managed with
catheter-directed thrombolysis.[11] Major differences to our case are that PE was found in the very late postoperative
period, catheter-directed thrombolysis was not administered into the same side of
the lung that needed surgery, and we used USAT with EKOS instead of solely catheter-directed
thrombolysis.
To the best of our knowledge, this is the first case demonstrating that USAT is feasible
in acute PE directly after lobectomy with reduced pulmonary reserve. Together with
previous cases from our clinic,[6] we conclude that USAT might be the most favorable approach in postoperative patients
with high-risk PE even when administered directly into pulmonary circulation after
lung surgery.
