RU2843438C1 - Method for choosing a surgical approach to an isolated injury of the superficial femoral artery with underlying obliterating atherosclerosis - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention relates to medicine, specifically to cardiovascular surgery, and can be used for choosing a surgical approach to the patients with an isolated injury of the superficial femoral artery with underlying obliterating atherosclerosis. Contrast computed tomography is used to determine, in a point system, an intensity of atherosclerotic stenosis, an extent of atherosclerotic plaque. Proximal, middle and distal segments of the superficial femoral artery are separately assessed. That is followed by determining a degree of arterial wall calcinosis and the presence of previous surgeries on the superficial femoral artery. Points are summed up for each segment of the superficial femoral artery; a surgical approach is chosen for an isolated lesion of the superficial femoral artery with underlying obliterating atherosclerosis (PMDi). At PMDi ≤ 35, choose an endovascular surgical approach, if the PMDi index is from 36 to 60, an endovascular approach is started, and if it is unsuccessful, an open surgery is performed, and if the PMDi index ≥ 60, choose open approach of surgical treatment.

EFFECT: method enables choosing a surgical approach ensured by determining an extension of the femoropopliteal segment involvement.

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Description

The invention relates to the field of medicine, namely to cardiovascular surgery, and can be used to select tactics for surgical treatment of patients with isolated lesions of the superficial femoral artery against the background of obliterating atherosclerosis.

The closest to the claimed invention is a method for selecting tactics for surgical treatment of patients with multilevel lesions in obliterating atherosclerosis of the aorta and arteries of the lower extremities, consisting in assessing the severity of atherosclerotic stenosis in % and the length of the atherosclerotic plaque in cm in the aorta, iliac, femoral, popliteal and tibial arteries of the lower extremities using contrast computed tomography [Patent of the Russian Federation 2756422. Method for selecting tactics for surgical treatment of patients with obliterating atherosclerosis of the arteries of the lower extremities / P.D. Puzdryak, A.E. Smirnov, V.V. Shlomin, I.M. Kositsyna, M.A. Ivanov, P.B. Bondarenko, K.V. Samko, K.A. Petrova, K.A. Komissarov, I.A. Kolchinsky. Appl. 06/29/2020 Publ. September 30, 2021].

The prototype is based on international principles of determining surgical tactics according to the TASC II classification. Table No. 1 presents the types of lesions of the femoropopliteal segment, varying in the degree of stenosis and the length of the atherosclerotic plaque in accordance with TASC II. The types of lesions of the femoropopliteal segment according to TASC II are also shown in Figs. 1-4.

Table 1

Types of lesions of the femoropopliteal segment according to the prototype method

TASC A lesion (Fig. 1)
- single stenosis of the SFA ≤ 10 cm in length
- single occlusion ≤ 5 cm in length TASC B lesion (Fig. 2)
- multiple lesions (stenosis or occlusion), ≤ 5 cm in length each
- single stenosis or occlusion ≤ 15 cm not involving the popliteal artery below the knee space
- single or multiple lesions of continuous tibial vessels to improve inflow for distal bypass
- heavily calcified occlusions ≤ 5 cm in length
- single stenosis of the popliteal artery TASC C lesion (Fig. 3)
- multiple stenoses or occlusions with a total length of >15 cm with or without severe calcification
- recurrent stenosis or occlusion requiring treatment after two endovascular interventions TASC D lesion (Fig. 4)
- chronic total occlusion of the OBA or SBA (> 20 cm with involvement of the popliteal artery)
- chronic total occlusion of the popliteal artery and the proximal part of its trifurcation

TASC II specifies types of lesions A, B, C, D. For types A and B, endovascular treatment is recommended, while for types C and D, open surgical treatment is recommended. The method involves differentiation by the degree of stenosis and the extent of atherosclerotic lesions and does not offer a comprehensive assessment of various isolated combinations of lesions of the superficial femoral artery in peripheral atherosclerosis and, accordingly, the choice of surgical treatment tactics for such lesions [Norgen L., Hiatt W.R., Dormandy J.A. et al. Inter-Society Consensus for the management of Peripheral Arterial Disease (TASC II) // Eur. J. Vasc.Endovasc. Surg. - 2007. - Vol.3. - Suppl 1. - P.1-75].

The disadvantage of the method that we chose as a prototype is the lack of consideration of the influence of such characteristics as calcification of the arterial wall, arterial diameter, the presence of previous operations and the availability of suitable autovenous material for performing a bypass operation, which, together with other factors, influences the tactics of choosing a surgical treatment method for isolated damage to the superficial femoral artery (SFA).

The technical result of the invention consists in improving the results of surgical treatment of patients due to a more detailed study and qualitative analysis of isolated damage to the superficial femoral artery against the background of obliterating atherosclerosis.

The technical result of the invention is achieved in that in the method for selecting tactics for surgical treatment of patients with isolated lesions of the superficial femoral artery against the background of obliterating atherosclerosis, including an assessment using contrast computed tomography of the severity of atherosclerotic stenosis in %, the length of the atherosclerotic plaque in cm, the degree of calcification of the arterial wall and the presence of previous surgical interventions on the superficial femoral artery, according to the invention, with the severity of atherosclerotic stenosis of the superficial femoral artery ≤ 59%, the obtained value is assigned 0 points, from 60% to 99% - 2 points, with a value of the severity of atherosclerotic stenosis equal to 100%, 4 points are assigned; if the length of the atherosclerotic plaque is ≤ 5 cm, the obtained value is assigned 0 points, from 6 to 10 cm - 2 points, from 11 to 15 cm - 3 points, > 15 cm - 4 points, in the absence of calcification of the arterial wall, 0 points are assigned, if calcification occupies ≤ 50% - 2 points, > 50% - 4 points, in the absence of surgical interventions on the superficial femoral artery or the presence of previous balloon angioplasty, 0 points are assigned, previous stenting - 2 points, loop endarterectomy - 4 points with subsequent summation of points for all affected segments of the superficial femoral artery and the choice of tactics for surgical treatment of isolated lesion of the superficial femoral artery against the background of obliterating atherosclerosis is determined by the formula:

, Where

PMDi - index of choice of arterial reconstruction in case of femoropopliteal segment lesions;

P is the sum of points in the L1 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

M is the sum of points in the L2 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

D - the sum of points in the L3 segment according to the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, the presence of previous operations;

with PMDi ≤ 35, endovascular tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are recommended; with PMDi from 36 to 60, an attempt at endovascular correction is recommended; if it is unsuccessful, open surgery is recommended; and with PMDi ≥ 60, open tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are chosen.

For better understanding, Fig. 5 shows a schematic representation of the infrainguinal segment of the arteries and anatomical structures of the thigh. In Fig. 5, the following are designated: 1 - common femoral artery, 2 - deep femoral artery, 3 - superficial femoral artery, 4 - inferior opening of the adductor canal (Hunter's canal), 5 - popliteal artery. 6 (P - proximal) - the distance from the orifice of the SFA to the middle of the distance (between the orifice of the SFA and the exit from Hunter's canal at the level of the septum intermusculare vastoadductorium), 7 (M - middle) - the distance from the middle to the exit from Hunter's canal, 8 (D - distal) - the distance from the exit from Hunter's canal to the P1 segment of the popliteal artery.

For each of the above sections, criteria for assessing the degree of vessel damage have been developed. If the severity of atherosclerotic stenosis (ST, %) of each of the above segments individually is ≤ 59%, the obtained value is assigned 0 points, from 60% to 99% - 2 points, if the severity of atherosclerotic stenosis is 100%, it is assigned 4 points, while the maximum degree of stenosis for the segment is assessed. If the length of the atherosclerotic plaque (L) is ≤ 5 cm, the obtained value is assigned 0 points, from 6 to 10 cm - 2 points, more than 10 cm - 4 points.

The presence and severity of calcification (Ca) are assessed as follows: absence (0%) - 0 points, isolated parietal calcification (≤ 50%) - 2 points, pronounced extended calcification (≥ 50%) - 4 points.

The degree of calcification is determined on a transverse CT section of the arterial wall by the % of the circumference length occupied by calcium grain inclusions. Fig. 6 shows a schematic image of a section with no calcification (0 points), Fig. 7 shows a schematic image of a section with calcification occupying less than 50% of the circumference (2 points), Fig. 8 shows a schematic image of a section with calcification occupying more than 50% of the circumference. An assessment is made of previous surgical interventions (Re-do) on the SFA: balloon angioplasty without stenting - 0 points, balloon angioplasty with stenting - 2 points, loop endarterectomy - 4 points.

The next step is to calculate the sum of all points obtained after analyzing the above-mentioned P, M and D segments of the PBA using a specially developed mathematical formula.

The choice of tactics for surgical treatment of isolated lesions of the superficial femoral artery against the background of obliterating atherosclerosis (PMDi index) is determined by the formula:

, Where

PMDi - index of choice of arterial reconstruction method for isolated lesions of the superficial femoral artery;

P is the sum of points in the L1 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

M is the sum of points in the L2 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

D - the sum of points in the L3 segment according to the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, the presence of previous operations;

48 - the maximum sum of points for all studied parameters of damage.

With PMDi ≤ 35, endovascular tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are predominantly chosen; with PMDi from 36 to 60, an attempt at endovascular correction is recommended; if it is unsuccessful, open surgery is recommended; and with PMDi ≥ 60, open tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are chosen.

If the sum of points prevails in favor of open surgical tactics, the diameter of the superficial femoral artery and the presence of a sufficient diameter of the autovein are additionally assessed. In case of diagnosis of aneurysmal dilation of the SFA, a bypass operation is recommended using a suitable autovein or, if it is not available, a synthetic prosthesis.

The method is carried out:

CT angiography of the aorta and arteries of the lower extremities is performed on a SIEMENS SOMATOM Definition AS 64 CT scanner with a 1536 mm topogram (depending on the patient's height) in the craniocaudal direction (from the diaphragm (thoracoabdominal aorta) to the distal sections of the lower leg arteries. After intravenous administration of the contrast agent Omnipaque 350 mg (iodine) / ml - 90 ml + 50 ml of saline solution at an injection rate of 4.5 ml / sec for 33 sec, scanning is performed, after which MPR, MIP and VRT reconstructions are performed using a specialized Angio Run Off program with the appropriate study settings (slice thickness - 5.0 mm; slice reconstruction - 1.0 mm; pitch: 0.9; increment: 0.7; Kernel: B26f medium smooth ASA; Angio window).

The reconstruction is performed with a slice thickness of 1 mm, which allows for a detailed assessment of the artery’s course and obtaining good VRT images, the so-called volumetric images.

After that, the results of CT angiography of the aorta and lower extremity arteries are assessed. During the study, the CT VASCULAR workflow was assigned. In this workflow, preliminary image processing and VRT construction took place, and a standard set of tools for measuring the % of arterial stenosis is also located in this workflow. Stenoses were measured distally to the located reference point (minimally changed section of the artery) or at the level of stenosis in relation to the outer wall counter (in the case of total calcification).

Then, according to the CT results, the severity of atherosclerotic stenosis in % and the length of the atherosclerotic plaque in cm are schematically depicted, the native diameter of the arteries, the presence of calcification of the arterial wall, previously implanted stents and their patency in the main arteries of the lower extremities: SFA, RCA are assessed.

According to the proposed algorithm, based on the data obtained from CT angiography, points are assigned to the corresponding changes.

If the severity of atherosclerotic stenosis (ST,%) of each of the above-mentioned segments individually is ≤ 59%, the obtained value is assigned 0 points, from 60% to 99% - 2 points, if the severity of atherosclerotic stenosis is 100%, it is assigned 4 points.

If the length of the atherosclerotic plaque (L) is ≤ 5 cm, the obtained value is assigned 0 points, from 6 to 10 cm - 2 points, more than 10 cm - 4 points.

The presence and severity of calcification (Ca) are assessed as follows: absence - 0 points, isolated parietal calcification - 2 points, pronounced extended calcification - 4 points.

An assessment is made of previous surgical interventions (Re-do) on the PFA: balloon angioplasty without stenting - 0 points, balloon angioplasty with stenting - 2 points, loop endarterectomy - 4 points.

After calculating the PMDi index using a specially developed formula, a decision is made on the choice of surgical intervention tactics according to the algorithm.

The choice of tactics for surgical treatment of isolated lesions of the superficial femoral artery against the background of obliterating atherosclerosis is determined by the formula:

,

PMDi - index of choice of arterial reconstruction in case of femoropopliteal segment lesions;

P is the sum of points in the L1 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

M is the sum of points in the L2 segment based on the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, and the presence of previous operations;

D - the sum of points in the L3 segment according to the severity of the lesion (% stenosis), the extent of the lesion, the presence of calcification of the arterial wall, the presence of previous operations;

48 - the maximum sum of points for all studied parameters of damage.

With PMDi ≤ 35, endovascular tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are predominantly chosen; with PMDi from 36 to 60, an attempt at endovascular correction is recommended; if it is unsuccessful, open surgery is recommended; and with PMDi ≥ 60, open tactics of surgical treatment of obliterating atherosclerosis of the arteries of the lower extremities are chosen.

To select the open method, the diameter of the artery and the presence of a suitable autovein are additionally assessed. In case of detection of aneurysmal expansions of the SFA, a bypass operation is recommended using an autovein or, if it is not available, a synthetic prosthesis.

The claimed invention is explained by examples.

Example 1

Patient K., 70 years old, has been suffering from intermittent claudication syndrome against the background of obliterating atherosclerosis of the lower extremity arteries for a year. Multispiral computed tomography (MSCT) revealed the following changes in the right femoropopliteal segment: isolated short occlusion of the right superficial femoral artery with a length of 4 cm, on axial sections of MSCT the arterial wall of the SFA with calcification occupying less than 50% of the arterial circumference.

This example is accompanied by the following images:

Fig. 9 - 3D model of MSCT angiography of the infrainguinal segment of the arteries (front view) . 9 - short occlusion (3.98 cm) of the superficial femoral artery in the D-distal segment.

Fig. 10 - 3D model of MSCT angiography of the infrainguinal segment of the arteries (posterior view) . 9 - short occlusion (3.98 cm) of the superficial femoral artery in the D-distal segment.

Fig. 11 - Axial sections of MSCT angiography of the infrainguinal segment of the arteries. 10 - occluded superficial femoral artery with calcium inclusion in the arterial wall (occupies less than 50% of the circumference).

Table 2 defines the scores according to the diagnosed lesion of the superficial femoral artery, presented in the anatomical diagram (Fig. 4, 5).

PBA segment % stenosis,
points L, points Sa, points Re, points L1 0 0 0 0 L2 0 0 0 0 L3 4 0 0 0 Total, points 4 Artery diameter - normal

Results: according to the obtained PMD index (8.3%), endovascular surgical treatment was recommended. The patient underwent endovascular balloon angioplasty and stenting of the SFA with a satisfactory clinical effect.

Example 2

Patient N., 68 years old, has been suffering from intermittent claudication syndrome against the background of obliterating atherosclerosis of the lower extremity arteries for a long time. Multispiral computed tomography (MSCT) revealed the following changes in the left femoropopliteal segment: isolated occlusion of the left superficial femoral artery with a length of 24.95 cm, on axial sections of MSCT the arterial wall of the SFA with minimal calcium inclusions.

This example is accompanied by the following images:

Fig. 12. 3D model of MSCT angiography of the infrainguinal segment of the arteries (front view) . 11 - extended occlusion (24.95 cm) of the superficial femoral artery in the segments P-proximal, M - middle, D - distal.

Fig. 13. Axial sections of MSCT angiography of the infrainguinal segment of the arteries. 12 - stenotic superficial femoral artery with no calcium inclusions in the arterial wall.

Table 3 defines the scores according to the diagnosed lesion of the superficial femoral artery, presented in the anatomical diagram.

PBA segment % stenosis,
points L, points Sa, points Re, points L1 4 3 0 0 L2 4 3 0 0 L3 4 0 0 0 Total, points 18 Artery diameter - normal
Suitable autovein - normal diameter on ultrasound angioscanning

= 37.5%.

Results: according to the obtained PMD index (37.5%), endovascular or open surgical treatment is recommended. An attempt at endovascular recanalization was unsuccessful. Given the presence of an artery of normal diameter and a suitable autovein, three methods of surgical correction are possible: autovenous femoropopliteal bypass grafting above the knee joint space (AFPS), loop endarterectomy, AFPS with a synthetic prosthesis.

The patient underwent open loop endarterectomy of the left lower limb SFA with a satisfactory clinical effect.

Example 3

Patient H., 65 years old, has been suffering from intermittent claudication syndrome against the background of obliterating atherosclerosis of the lower extremity arteries for 3 years. Previously, the patient underwent stenting of the superficial femoral artery for multilevel hemodynamically significant stenoses. One year after the endovascular procedure, the symptoms of intermittent claudication recurred. Multispiral computed tomography (MSCT) revealed the following changes in the left femoropopliteal segment: extended reocclusion of the stented SFA with a length of 35 cm. Given the presence of a stent in the SFA along its entire length, it is impossible to objectively assess the degree of calcification of the artery.

This example is accompanied by the following images:

Fig. 14. 3D model of MSCT angiography of the infrainguinal segment of the arteries (front view) . 13 - extended reocclusion (35.00 cm) of the previously stented superficial femoral artery in the P-proximal, M-middle, D-distal segments.

Fig. 15. 3D model of MSCT angiography of the infrainguinal segment of the arteries (posterior view) . 13 - extended reocclusion (35.00 cm) of the previously stented superficial femoral artery in the P-proximal, M-middle, D-distal segments.

Table 4 defines the scores according to the diagnosed lesion of the superficial femoral artery, presented in the anatomical diagram.

PBA segment % stenosis,
points L, points Sa, points Re, points L1 4 4 0 2 L2 4 4 0 2 L3 4 4 0 2 Total, points 30 Artery diameter - normal
Suitable autovein - normal diameter on ultrasound angioscanning

= 62.5%.

Results: according to the obtained PMD index (62.5%), open surgical treatment is recommended. Given the presence of an artery of normal diameter and a suitable autovein, three methods of surgical correction are possible: autovenous femoropopliteal bypass above the knee joint space (AFPS), loop endarterectomy, AFPS with a synthetic prosthesis.

The patient underwent open loop endarterectomy of the left lower limb SFA with a satisfactory clinical effect.

Claims (7)

A method for selecting surgical treatment tactics for patients with isolated lesions of the superficial femoral artery against the background of obliterating atherosclerosis, including determination of the severity of atherosclerotic stenosis and the extent of an atherosclerotic plaque using contrast computed tomography, characterized in that the proximal, middle, and distal segments of the superficial femoral artery are assessed separately, and the degree of arterial wall calcification and the presence of previous surgical interventions on the superficial femoral artery are additionally determined; with the severity of atherosclerotic stenosis of the superficial femoral artery ≤ 59%, 0 points are assigned, from 60% to 99% - 2 points, 100% - 4 points; if the length of the atherosclerotic plaque is ≤ 5 cm, 0 points are assigned, from 6 to 10 cm - 2 points, from 11 to 15 cm - 3 points, > 15 cm - 4 points, in the absence of calcification of the arterial wall, 0 points are assigned, if calcification occupies ≤ 50% - 2 points, > 50% - 4 points, in the absence of surgical interventions on the superficial femoral artery or the presence of previous balloon angioplasty, 0 points are assigned, stenting - 2 points, loop endarterectomy - 4 points, the points are summed up for each segment of the superficial femoral artery, the choice of tactics for surgical treatment of isolated lesion of the superficial femoral artery against the background of obliterating atherosclerosis is determined by the formula: PMD index=((P+M+D)*100%)/48, where PMDi – index of choice of arterial reconstruction in case of femoropopliteal segment lesions; P – sum of points in the proximal segment; M – the sum of points in the average segment; D – sum of points in the distal segment, with PMDi ≤ 35, endovascular surgical treatment tactics are chosen; with PMDi from 36 to 60, they start with endovascular tactics, and if it is unsuccessful, they move on to open surgery; and with PMDi ≥ 60, open surgical treatment tactics are chosen.