Dr. Pecchioni Emails Flashcards Preview

Vascular > Dr. Pecchioni Emails > Flashcards

Flashcards in Dr. Pecchioni Emails Deck (12)
Loading flashcards...
1

A 68 yo F develops heparin induced thrombocytopenia (HIT) on postoperative day 8 following exploratory laparotomy for adhesive disease. She received prophylactic subcutaneous heparin following the procedure. Her postoperative course has been complicated by acute myocardial infarction, acute renal failure, prolonged ileus, and now, thrombocytopenia (platelets 48,000/uL) and associated deep venous thrombosis. Which of the following is the most appropriate treatment for this patient?

a. fondaparinux
b. lepirudin
c. argatroban
d. bivalirudin
e. low molecular weight heparin

This patient presents with typical-onset heparin-induced thrombocytopenia (HIT), which occurs 5-14 days following heparin exposure. A platelet decrease of >50% baseline value or nadir of <100,000/uL occurring days 5-9 following heparin exposure should prompt evaluation of HIT. In addition, new thrombosis or skin necrosis should raise the clinician's suspicion. Once clinical suspicion of HIT is established, serologic tests (PF4 antibodies or serotonin release assays) should be sent to confirm the diagnosis. Treatment includes eliminating heparin exposure to include heparin intravenous flushes and heparin coated catheters. Low molecular weight heparin has some cross reactivity with HIT antibodies. Direct thrombin inhibitors (argatroban, lepirudin, and bivalirudin) are approved for treatment of HIT. All three medications are titrated based on aPTT. There is no reversal agent for these medications; therefore, the drug half-life is very important when planning interventions (argatroban - 50 min, lepirudin - 80 min, and bivalirudin - 25 min). In addition, argatroban is eliminated via the hepatobiliary system and should not be used in patients with liver dysfunction. Both lepirudin and bivalirudin undergo renal execretion. Bivalirudin also undergoes enzymatic breakdown in serum (accounts for 80% of elimination). If utilizing bivalirudin for distal bypass surgery with a tourniquet, the concentration of bivalirudin in the distal bed will decrease rapidly secondary to enzymatic breakdown and should be used with caution. In this patient, argatroban is the best treatment option given her renal dysfunction. Fondaparinux is the only anti-Factor Xa agent available in the U.S.. Fondaparinux does not cross react with HIT antibodies; therefore, it should be safe in patients with HIT. It is not approved for treatment of acute HIT. If used in the treatment of HIT, it is better utilized to bridge patients to Warfarin once they are no longer hypercoagulable. Fondaparinux is also cleared by the kidneys.

2

Which of the following intraoperative maneuvers would facilitate exposure of the superior mesenteric artery (SMA) at the typical location for SMA embolectomy?
a. mobilization of the 4th portion of the duodenum to allow the root of the mesentery to be grasped
b. division of the inferior mesenteric vein
c. retraction of the superior mesenteric vein to the patient's left
d. caudal retraction of the transverse mesocolon Incorrect
e. cephalad retraction of the left renal vein

The anatomy of the superior mesenteric artery (SMA) and its relationship to surrounding structures is vital to exposing the SMA for the open surgical treatment of both acute and chronic mesenteric ischemia. To perform SMA embolectomy, most surgeons expose the SMA in the root of the small bowel mesentery inferior to transverse mesocolon. Infra-mesocolic exposure of the SMA requires cephalad displacement of the transverse colon. For most open exposures of the SMA from an anterior, trans-abdominal approach (ie, not via a left flank or retroperitoneal approach), the artery is exposed near the root of the mesentery at a location inferior to the pancreas and distal to the point at which the SMA crosses over the duodenum. At this location, the SMA can be palpated in the mesentery in most cases, even if it is pulseless. A longitudinal incision in the anterior leaflet of the mesentery in this location will allow exposure of the SMA in the vicinity of the middle colic artery branch. If the superior mesenteric vein is encountered, dissection should proceed to the patient's left to identify the proximal superior mesenteric artery.

Many surgeons find it helpful to mobilize the 4th portion of the duodenum to allow the root of the mesentery to be grasped between the palm of the hand (posterior to the root of the mesentery) and the thumb (rolling over the SMA anteriorly). Although this maneuver can be helpful, it is not universally required for exposure of the SMA in that location. Of the choices available in this question, none of the maneuvers would facilitate exposure, except for mobilization of the 4th portion of the duodenum.

3

A 45 yo woman presents with extensive medial thigh superficial venous cording and associated erythema and tenderness. Duplex ultrasonography confirms superficial thrombophlebitis (5 cm in length) of her greater saphenous vein at the level of the mid- and distal-thigh (>3cm distal to the saphenofemoral junction). Which of the following is the most appropriate initial treatment?
A. Non-steroidal anti-inflammatory agents (NSAIDs)
B. Warm compress, ambulation, and compression
C. Therapeutic anticoagulation with Coumadin
D. Prophylactic fondaparinux
E. Radiofrequency ablation

The inflammatory-thrombotic process of the superficial veins is termed superficial venous thrombosis (SVT). SVT is associated with a 6-53% risk of DVT and 0-10% risk of pulmonary embolism. While mild disease may still be managed simply with NSAIDs, compression, and warm compresses, patients with moderate disease, defined as SVT at least 5 cm in length and located at least 3cm distal to the saphenofemoral junction, should be managed more aggressively with either prophylactic low molecular weight heparin or fondaparinaux. This management is based on data from the The Superficial Thrombophlebitis Treated by Enoxaparin Study Group and, more recently, The CALISTO Study Group for the Treatment of Superficial-Vein Thrombosis in the Legs. Decousus et al assessed the safety and efficacy of fondaparinaux for SVT with an international, multi-center, randomized, double-blind, placebo-controlled trial that assessed 3002 patients with acute, symptomatic lower limb SVT involving a segment at least 5 cm in length located at least 3 cm distal to the SFJ. These patients were assigned to 45 days of treatment with fondaparinaux (2.5 mg administered subcutaneously daily), or placebo. The fondaparinaux group demonstrated an 85% lower rate of pulmonary embolism or DVT than the placebo group after 77 days, along with a significantly reduced rate of symptomatic SVT recurrence or SVT extension to the SFJ, all without increased major bleeding or serious adverse events. Therapeutic anticoagulation still applies to any patient that develops concomitant or subsequent deep venous thrombosis or PE. For patients who cannot tolerate anticoagulation, GSV disconnection and ligation at the SFJ remains appropriate. Surgical treatment with GSV ablation, along with phlebectomies of the involved branch varicosities, should be considered the optimal treatment for patients with symptomatic SVT and evidence of superficial venous insufficiency/reflux confirmed by Duplex ultrasound, which is usually performed after the phlebitis has resolved.

4

A 62-year-old, right handed man with a history of automatic implantable cardioverter defibrillator (AICD) placement in the left chest area 10 years previously presents for progressive chronic kidney disease (CKD). He is expected to need hemodialysis within the next 3 months. On exam in the office, he has normal brachial, radial, and ulnar pulses, with a normal Allens test bilaterally. He has visible cephalic veins bilaterally, which appear to be about 3.5 mm at the wrist and 5 mm in the upper arm. They are clearly seen in continuity throughout the entire arm. The veins in the shoulder region are clearly visible in the left upper extremity only. Which of the following is the appropriate next step in the management of this patient?
a. place a brachiocephalic autogenous AV access on the left
b. perform a radiocephalic autogenous AV access at the wrist on the left
c. perform vein mapping of both upper extremities to assess the cephalic and basilic veins
d. perform venogram to assess for central vein stenosis Correct
e. perform upper extremity arterial duplex to assess arterial supply

This patient has an AICD in the left subclavian vein, placing him at risk for central venous lesions. As he is right handed, a left access would be preferred if the anatomy is suitable. A retrospective study assessed AVF and AVG success as compared to preoperative method of assessment. Group 1 had a higher rate of elderly patients, a higher mean number of prior central catheters, and underwent preoperative imaging and intervention for underlying central venous stenosis prior to access construction. Group 1 had a 90% success rate in access placement and a longer mean patency rate for the access. The other group had a 69% success rate without preoperative assessment. The study identified 66 central venous stenosis in 260 patients studied.

I think I omitted the actual answer for last week’s question. The answer is D.

He is R handed, so you would like to make his AVF on the Left side. He has an AICD though that his creating an venous outlet obstruction based on the finding that his “veins in the shoulder region are clearly visible in the left upper extremity only”. You have to do the venogram first to r/o and/or treat the obstruction before creating an AVF on the left.

5

A 62-year-old man with a history of bilateral internal carotid artery disease for many years presents following routine annual duplex surveillance. The patient is asymptomatic from his carotid artery disease. Duplex examination reveals:

Right Left
CCA PSV 100 cm/s 79 cm/s
ICA PSV 240 cm/s 0 cm/s
CCA EDV 30 cm/s 41 cm/s
ICA EDV 110 cm/s 0 cm/s

Using evidence-based medicine, which of the following is the recommended therapy for this patient?

Select one:
a. carotid angioplasty and stenting with embolic protection
b. carotid endarterectomy with patch
c. carotid endarterectomy without patch
d. best medical therapy Correct
e. carotid angioplasty and stenting without embolic protection

The best therapy option to reduce this patient's risk of stroke is medical therapy. Because the left internal carotid artery is occluded, the velocities on the right internal carotid artery are elevated. In this situation, the peak systolic velocity (PSV) and end diastolic velocity (EDV) are not reliable to determine the degree of stenosis. The ratio of the ICA/CCA PSV is valuable in situations of either low flow or high flow. In this example, the ratio on the right is 2.4, well below the 4.0 ratio threshold for a 70% stenosis. Thus, the stenosis on the right is consistent with < 70% stenosis. According to the Asymptomatic Carotid Surgery Trial (ACST), this patient, who is asymptomatic, would not benefit from surgical intervention of the right carotid artery disease.

6

Thoracoscopic sympathectomy is a highly effective treatment for which of the following conditions:

Select one:
a. truncal hyperhidrosis
b. palmar hyperhidrosis
c. horner’s syndrome
d. complex regional pain syndrome
e. digital vasoocclusive disease with ulceration

Thorascopic sympathectomy has been used to treat a number of upper extremity conditions and is an effective treatment for palmar hyperhidrosis. It is a less effective treatment for complex regional pain syndrome of the upper extremity or for Raynaud's-related ulceration. Local (digital) sympathectomy may assist healing of an ulceration caused by digital vasoocclusive disease. The most common complication of thoracoscopic sympathectomy for palmar hyperhidrosis is axillary and truncal sweating. Injury to the stellate ganglion during sympathectomy results in Horner's syndrome.

7

A 55 year old male is undergoing open repair of an infrarenal abdominal aortic aneurysm. Which of the following is the best indication for reimplantation of the inferior mesenteric artery?
a. Brisk back bleeding from transected IMA
b. Aneurysm measuring greater than 7 cm in maximal diameter
c. Occluded right internal iliac artery
d. Occluded superior mesenteric artery
e. Occluded IMA on preoperative CT scan

The inferior mesenteric artery is usually ligated during open abdominal aortic aneurysm repair. Unfortunately, this can place the patient at risk for postoperative colonic ischemia under certain conditions. If the IMA is occluded on preoperative imaging or is found to be occluded intraoperatively, ligation is unlikely to cause colonic hypoperfusion. Conversely, an open IMA that vigorously back-bleeds implies a large amount of intact collateralization from the SMA and iliac vessels. Aneurysm size is not correlate with risk for colonic ischemia. An occluded SMA, however, places the patient at serious risk for visceral hypoperfusion if the IMA is ligated.

8

Which herbal supplement is least likely to increase the risk of peri-operative bleeding?
a. St John's wort
b. ginseng
c. ginkgo
d. ephedra
e. garlic

St John's wort

Vascular surgeons should understand which herbal supplements are being used by their patients, as several supplements are known to have potentially harmful effects in the peri-operative period. Bleeding risks are of particular concern.

Approximately 12% of the US population uses supplements, but use may be higher among patients undergoing surgery. Furthermore, because patients may not report herbal supplement use, it is important for healthcare providers to specifically ask preoperative patients about their use. It is also important to recognize that herbal supplements are not subject to the same FDA scrutiny regarding safety and efficacy as over-the-counter and prescription drugs, and that different preparations of the same supplement can have variable effects.

Garlic, ginkgo, and ginseng can all effect platelet function. For garlic and ginseng, the effects can be irreversible, whereas for ginkgo, the effects are reversible. Therefore, for major surgical procedures with a significant bleeding risk, ginkgo should be held for at least 2 days, and garlic and ginseng should be held for at least a week.

Ephedra, known as ma huang in Chinese medicine, contains alkaloids such as ephedrine, pseudoephedrine, and norephedrine. Ephedra causes an increase in blood pressure and heart rate and can therefore cause increased bleeding via its sympathomimetic effects.

St John's wort is an herb that is used for the treatment of depression. St John’s wort does not have anticoagulant effects. It induces the cytochrome P450 system, which may increase metabolism of many prescription drugs, including warfarin. Thus, it may decrease the anticoagulant effectiveness of warfarin.

9

A 77-year-old woman underwent left carotid endarterectomy (CEA) one year ago that was complicated by a perioperative MI. She has been admitted for exacerbation of CHF in the past 6 months. She presents now with symptoms of left hemispheric TIA. Her left carotid duplex shows a PSV 330 cm/sec and EDV 145 cm/sec. Which of the following is both the probable cause of her symptoms and the appropriate treatment for this patient?
a. intimal flap from technical error during prior CEA; L carotid interposition graft
b. recurrent atherosclerosis; repeat L CEA
c. recurrent atherosclerosis; L carotid interposition graft
d. intimal hyperplasia after prior CEA; L carotid stent
e. intimal hyperplasia after prior CEA; repeat L CEA

d. intimal hyperplasia after prior CEA; L carotid stent

Recurrent carotid stenosis occurs in up to 20% of patients after CEA and is time-dependent regarding the cause of restenosis. Narrowing that occurs within ~2 years of the index procedure is usually due to intimal hyperplasia at the operative site. Recurrent carotid stenosis more than 2 years after CEA is most commonly from recurrent atherosclerosis. Technical errors resulting in ipsilateral hemispheric symptoms usually occur in the immediate post-operative period rather than remotely. Due to the histopathologic changes in the carotid artery after CEA, repeat endarterectomy may not be technically feasible. Open repair of recurrent carotid stenosis may require an interposition vein graft from the common carotid to the internal carotid artery distal to the site of stenosis. In addition, cranial nerve injury is significantly higher with repeat carotid sugery. Consistent with current Center for Medicare Services (CMS) guidelines for high-risk carotid surgery, treatment with a left carotid stent for this patient with symptomatic, recurrent high-grade (>70%) stenosis would be appropriate.

Clinical series have shown that CAS in the setting of recurrent carotid stenosis after CEA is equivalent to redo CEA with regard to peri- and post-operative stroke/death rates, as well as stroke-free survival. Redo CEA, however, was associated with a significant increase in cranial nerve injuries (14% redo-CEA vs. 0% CAS). When compared to CAS for primary carotid atherosclerosis, CAS for recurrent carotid stenosis resulted in significantly lower peri-operative stroke/death/MI rates, as well as lower combined early and late stroke rates. Physician-specific and institution-specific outcomes should be considered in the selection of the optimal treatment (CAS vs. redo CEA) for recurrent carotid stenosis.

10

A 47 year old male with diabetic neuropathy is currently dialyzing via a left brachio-axillary AV graft constructed 3 months ago after vein mapping showed no veins useable for autogenous access in either arm. After the access placement he gradually developed ulceration of the left 5th finger. Left 5th digit interphalyngeal amputation was performed by a hand surgeon one month prior, who referred the patient for vascular evaluation because of poor wound healing. Radial pulse is not palpable in either wrist. Digital pulse volume recordings are obtained. When the graft is compressed, waveforms in the left digits augment and are symmetrical with those of the right side. Which of the following would be LEAST appropriate?

a. Banding of the graft near the arterial anastomosis guided by digital plethysmography
b. Broad spectrum antibiotics and hyperbaric therapy
c. Ligation of the graft with placement of a graft in the dominant arm
d. Brachial artery ligation below the anastomosis, with saphenous vein bypass from the axillary to distal brachial artery (DRIL procedure)
e. Proximalization of the graft with a 3mm PTFE graft from the axillary artery and ligation of the current graft arterial anastomosis

b. Broad spectrum antibiotics and hyperbaric therapy

Hyperbaric therapy is unlikely to be of any benefit. All of the other procedures may be appropriate in selected patients to treat severe steal with digital gangrene.

11

After the diagnosis of DVT, anticoagulation with heparin or low-molecular-weight heparin is immediately begun. Which of the following is the appropriate next step in the management of DVT?
a. ambulation is encouraged, and compression should be applied as soon as the patient is anticoagulated
b. surgical compression is contraindicated in patients with DVT
c. bed rest and leg elevation should be used for at least 10 days after the diagnosis
d. bed rest and leg elevation should be used for the first 5 days after the diagnosis
e. thrombolysis should only be used in the face of impending lower extremity gangrene

a. ambulation is encouraged, and compression should be applied as soon as the patient is anticoagulated

The use of strong compression and early ambulation after DVT treatment can significantly reduce the pain and swelling resulting from the DVT. The rate and severity of postthrombotic syndrome after proximal DVT can be decreased by approximately 50% by the use of compression stockings. Discussion with the patient about the importance of compression is critical to ensure good compliance. Additionally, walking with good compression does not increase the risk of PE, whereas it significantly decreases the incidence and severity of the postthrombotic syndrome.

12

A 56-year-old man presents with complaints of intermittent right hip and buttock claudication and erectile dysfunction. On examination he has absent femoral pulses. The penile brachial index is 0.38 with a penile systolic pressure of 60 mmHg. The ankle brachial index and segmental blood pressures showed:
- Rt: Severely decreased right ankle pressure indices: 0.57/0.51.
Moderately decreased right great toe pressure 45mmHg (0.28).
Decrease of the right high thigh pressure.

- Lt: Severely decreased left ankle pressure indices: 0.46/0.54.
Moderately decreased left great toe pressure 51mmHg (0.32).
Decrease of the left high thigh pressure.

Based on published data, which of the following represents the appropriate intervention option for this patient?
a. open aortobifemoral bypass grafting
b. femoro-femoral bypass grafting
c. open cutdown of both groins and transluminal balloon angioplasty of the aorta and bilateral iliac arteries
d. percutaneous transluminal balloon angioplasty of the aorta and bilateral iliac arteries
e. axillobifemoral bypass grafting

emailed Pecchioni for answer on 3/27